writing

Best AI Proofreaders

The best AI proofreaders in September 2026, ranked on document-level editing rather than sentence-level grammar — Grammarly, ProWritingAid, PerfectIt, Scribbr, Writefull, Trinka, Paperpal, LanguageTool, Hemingway, Sapling, Ginger and InstaText — with verified pricing, tracked-changes support, and the benchmark evidence on how accurate automated correction actually is.

Updated September 2026

Quick answer: For most writers in September 2026 the best AI proofreader is Grammarly Pro at $12 per month on an annual plan, because it is the only commercial proofreader whose error-detection accuracy has been measured on a public academic benchmark by researchers with no commercial stake — 63.3 F0.5 on CoNLL-2014, ahead of both a purpose-built research system and ChatGPT (Wu et al., 2023). If you need every correction returned as a Word tracked change on a whole manuscript, use Scribbr’s AI Proofreader or Writefull Revise instead, both of which are built for that and Grammarly is not. If you are a professional editor enforcing a house style, PerfectIt does a job no general AI tool does: it checks a document against itself for consistency in hyphenation, capitalisation and acronyms.

The one caveat that applies to every tool on this page: no proofreading vendor publishes precision or recall figures for its production checker. Grammarly’s own engineering team wrote an article titled “Achieving Superior Precision and Recall in Grammatical Error Correction” and reported not a single number in it (Grammarly Engineering). Every accuracy claim you will read elsewhere in this category is either vendor marketing or an affiliate review. We have anchored this page in the independent research that does exist, and said “data not available” where it does not.

Prices below were verified on vendor pages on 7 September 2026. Four vendors were running promotions on that date, so list and promotional prices are shown separately.

What counts as a proofreader, and what this page is not

Three different products get called “AI proofreading”, and they solve different problems.

Proofreading is corrective and document-level. You have a finished draft. You want errors found and consistency enforced across the whole thing — including things that are only errors in context, like an acronym defined twice, a serial comma used in chapter two but not chapter seven, or a reference that does not match the citation style. That is what this page ranks.

Grammar checking is corrective and sentence-level. It flags a subject-verb disagreement in the sentence you are typing. Every proofreader includes a grammar checker; not every grammar checker is a proofreader. Tools that only check the sentence in front of you are ranked on best AI grammar checkers rather than here.

Generative writing tools produce new text. Claude, ChatGPT and the specialist drafting platforms are ranked in best AI for writing. They can proofread — see the section on using a general model below — but they are optimised to produce prose, not to leave prose alone.

Two adjacent pages are also distinct. Best AI humanizer covers rewriting intended to change how AI-detection systems classify a text; proofreading corrects errors and does not set out to alter provenance signals. Best AI detector covers detection itself. If you are a student, best AI for students and best AI for essays cover the wider stack; researchers should also see best AI for research.

How accurate are AI proofreaders in September 2026?

This is the question the category refuses to answer, so it is worth setting out what is actually known.

The benchmarks that exist

Automated correction is measured as grammatical error correction (GEC), and three public test sets dominate.

The metric matters. F0.5 weights precision twice as heavily as recall, on the assumption that flagging correct text is more damaging to a writer than missing an error. A tool that corrects everything scores badly even if it fixes every real mistake.

The best reported scores come from purpose-built research systems, not from products you can buy: 72.8 F0.5 on CoNLL-2014 and 81.4 on BEA-2019 from an ensemble published by Omelianchuk et al. (April 2024). The best single model on BEA-2019 is 78.70 (Staruch et al., BEA 2025).

Note that CoNLL-2014 is conventionally scored with M² and BEA-2019 with ERRANT. Scores produced by the other scorer are not comparable, and mixing them is the most common error in write-ups of this field.

Large language models over-correct, and the effect is measurable

The recurring finding across seven years of research is that general-purpose models have high recall and low precision: they find the errors, and then they keep going.

The clearest single illustration is from Türker and Eryiğit (BEA 2026), presented in July 2026, which benchmarked seven current models zero-shot. Instructing GPT-4.1 to make minimal edits rather than open-ended improvements moved its CoNLL-2014 precision from 57.26 to 70.37 while its recall fell from 65.84 to 52.73 — an almost exactly equal and opposite trade. The best model in that study on minimal-edit correction was Claude Sonnet 4.5 at 67.05 F0.5 on CoNLL-2014 and 64.91 on BEA-2019, which still leaves a 13.79-point gap on BEA-2019 against the best task-specific system. The authors read this as evidence of “the continued necessity of task-specific solutions”.

The earlier head-to-head is blunter. Wu et al. (2023) had two annotators audit 20 corrected sentences and counted 30 over-corrections from ChatGPT against one from Grammarly.

But the metrics are not the whole story, and this is the honest complication. Coyne et al. (2023) found GPT-4 scored 52.79 F0.5 on BEA-2019, roughly 20 points below purpose-built systems — while human raters scored its output 0.788 against 0.706 for the gold human reference edits. Raters preferred the model’s corrections to the corrections the benchmark calls correct. On fluency rewriting, where minimal-edit scoring does not apply, models now win outright: Claude Sonnet 4.5 reached 66.09 GLEU on JFLEG against 64.7 for the specialised baseline.

The most careful recent work quantifies the disagreement directly. Labib et al. (AIED 2026) took 1,730 corrections where a fine-tuned GPT-4o differed from the gold reference and had them adjudicated: 35.61% were judged better than the reference, 38.15% equally valid, and 26.24% worse. Roughly three-quarters of the model’s “errors” were not errors. The same study found the over-correction concentrated by error type: false insertion rates above 50% for adjectives and adverbs, against a 96% correction rate on spelling.

Practical takeaway: benchmark scores understate how good a general model is at proofreading and overstate how safe it is. A model will improve your prose and quietly change what it says. A specialist checker will leave your meaning alone and miss more.

Independent testing of commercial tools barely exists

This deserves stating plainly, because the rest of this category will not state it.

• The only independent test placing a commercial proofreader on a standard public benchmark with published precision and recall is Wu et al. (2023): Grammarly at P 67.3 / R 51.1 / F0.5 63.3 on 100 CoNLL-2014 sentences. That is a 100-sentence sample from 2023.
• The last multi-tool academic comparison is Sahu et al. (2020), which tested five tools against a 500-sentence error set: Grammarly scored highest at 44.4% overall accuracy and 99% on spelling, but no tool exceeded 11% accuracy on sentence-structure errors and none exceeded 25% on semantic errors. That study predates large language models entirely.
• A properly designed study of Grammarly’s precision and recall against expert human annotators, across 21 error categories, was published in the Journal of Second Language Writing on 1 March 2026. It is paywalled and its headline figures are not public. We are not going to quote numbers we have not read.
• For ProWritingAid, QuillBot, LanguageTool, Trinka, Paperpal, PerfectIt, Scribbr, Writefull, Hemingway, Sapling, Ginger and InstaText, independent quantitative accuracy testing is data not available. Every accuracy figure any of them publishes is self-generated.
• A systematic review of 24 studies of Grammarly in second-language writing contexts found that more than half of them (15) reported problems with its feedback (Dizon and Gayed, 2024).

Two vendor accuracy claims are worth naming because they get quoted as proofreading accuracy and are not. Grammarly’s #1 ranking on the RAID leaderboard (9 February 2026) and Trinka’s (July 2026) are both for AI-content detection, a different product. Paperpal’s “90% accuracy against QuillBot at 70% and Grammarly at 55%” comes from Paperpal benchmarking its own product on 20 passages.

The closest thing to third-party validation anywhere in this set is Writefull’s publisher case study, in which a scientific society’s editors reviewed 35,000 individual edits and found 99.04% applied without error and 0.96% introducing an error. That is a customer’s internal evaluation published by the vendor, not independent verification, and it measures a publisher-side API rather than the consumer product.

Best AI proofreaders in 2026: the ranking

Ranked on document-level capability, verified pricing transparency, and platform reach. Prices confirmed 7 September 2026.

1. Grammarly — best for most writers

Price: Free tier; Pro $12/month billed annually, or $30/month billed monthly (Grammarly, support); Enterprise by quote, delivered through Superhuman Go Free tier: spelling, basic grammar, tone detection, 100 AI prompts per month Pro adds: full-sentence rewrites, tone adjustment, English fluency suggestions, inclusive language, citation consistency, plagiarism detection, AI-text detection, 2,000 AI prompts per member per month Platforms: browser extensions, Windows and macOS apps, Microsoft Office, Google Docs, iOS and Android

Grammarly is the default for a reason that has nothing to do with marketing: it is the only tool here with an independently measured score on a public benchmark. In the Wu et al. (2023) test it reached 63.3 F0.5, beating the research system GECToR (60.8) and ChatGPT (53.1), and in the 20-sentence human audit it produced 14 under-corrections, zero mis-corrections and one over-correction. That profile — conservative, occasionally too conservative, almost never wrong when it does speak — is exactly what you want from a proofreader and exactly what a general language model does not give you.

Why it wins: the widest surface area of any tool in the category. It runs in essentially every place you write, the free tier is genuinely useful rather than a demo, and $12 a month buys the full corrective feature set.

Limitations: it is a real-time assistant, not a manuscript pass. There is no Word tracked-changes export, so an editor who needs to show a client what changed cannot use it for that. It has no LaTeX support. The standalone Desktop Editor apps were discontinued on 20 March 2024. Its document-level consistency features are thin next to PerfectIt’s — Pro gives you one style guide and one brand tone.

Corporate note that affects nobody’s writing but confuses everybody: Grammarly the company renamed itself Superhuman on 29 October 2025 (announcement), after acquiring Coda (announced 17 December 2024, closed January 2025) and the email client Superhuman (announced 1 July 2025, terms undisclosed). Grammarly remains the product name. grammarly.com still operates and still sells the Pro plan; only the parent company changed.

Best for: anyone who wants one tool that corrects competently everywhere they type.

2. ProWritingAid — best for long-form and manuscripts

Price: Free tier; Premium $10/month billed yearly ($120/year) at list, currently $7.50/month ($90/year) in a 25% “Storyteller’s Sale” running on 7 September 2026; $30/month billed monthly; lifetime $399 (ProWritingAid). Premium Pro is $12/month yearly at list, $9/month on sale, $36 monthly, $699 lifetime Free tier: 500 words at a time, each report runnable twice per day, 10 rephrases per day Platforms: Word, Google Docs, desktop editor, browser extension. English only — General, British, US, Australian and Canadian Education: free for K-12 educational organisations; 20% student discount

ProWritingAid is the strongest general tool for documents measured in chapters rather than paragraphs. Premium removes the word cap entirely and unlocks 25 or more writing analysis reports — readability, overused words, sentence variety, pacing, sticky sentences, echoes — which is the closest a mainstream tool gets to a structural edit. The custom style guide and custom dictionary let you enforce your own house rules and terminology across a manuscript, and the author-comparison feature benchmarks your prose against 90 fiction authors.

Limitations: no tracked-changes export and no LaTeX. Monthly plans are non-refundable and yearly plans carry only a three-day money-back window, which is short. The company runs near-permanent discounting, so the list price is close to notional. Story Credits for manuscript-level analysis are a separate purchase on top of the subscription.

Best for: novelists, non-fiction authors and anyone editing 20,000 words or more in one pass.

3. Scribbr AI Proofreader — best for academic work that needs tracked changes

Price: free error-assessment scan; the price of the paid AI Proofreader is not published on Scribbr’s own pages — data not available. Widely quoted figures appear to be recycling the $9.95 that Scribbr lists as the standalone value of the bundled Citation Checker, so we are not repeating them Human proofreading, by contrast, is priced clearly: from $0.017 per word plus a $25 setup fee; an 8,000-word document costs $161 at a 7-day turnaround, $229 at 3 days and $297 at 24 hours (Scribbr rates). Paper formatting is $1.95 per page per item; citation editing is $2.75 per source Platforms: web upload, .docx only

This is the tool that does the thing most students actually want: you upload a document and get back a Word file in which every change is a tracked change, accept or reject individually or all at once. Turnaround is capped at ten minutes. It includes a Consistency Checker for serial commas, quotation marks and dashes, and an APA Citation Checker with an interactive error report, bundled at no extra cost. It deliberately leaves your reference list alone.

Limitations: US English conventions only, which rules it out for UK, Australian and Canadian submissions. .docx input only. There is no free trial — the free scan tells you how many errors it found and what kinds, then you pay to see them. And the pricing opacity is a real mark against it in a category where competitors publish a table.

Ownership note: Scribbr was acquired by Course Hero in March 2022 and now sits in the Learneo portfolio alongside QuillBot and LanguageTool, both also on this page. Treat them as corporate siblings rather than independent alternatives.

Best for: students and researchers who need a tracked-changes .docx back and write in US English.

4. PerfectIt — best for professional editors and house style

Price: no free tier; 14-day free trial, no card required. The only price published on any official page is $90 per year, from a pricing announcement dated 30 November 2022 — nearly four years old, and the current store page renders no prices at all, so treat it as indicative. Current per-tier pricing: data not available. Discounts of at least 30% for members of ACES, CIEP, AMWA, APMP and IPEd Tiers: Professional, Elite (adds PowerPoint and long style sheets), Team (up to 100 users), Enterprise Platforms: Word for Windows add-in, PerfectIt Cloud for Mac and Word 365, PowerPoint on Elite and above. Not available for Google Docs or OpenOffice

PerfectIt is not a grammar checker and does not pretend to be. It checks a document against itself, which is the specific job no general AI tool does well: inconsistent hyphenation, capitalisation that drifts between sections, spelling variants from multiple contributors, numerals written two ways, acronyms that are never defined, defined twice, or defined differently in two places — and it will generate the acronym list for you. It enforces client style sheets through Styleworks and checks against The Chicago Manual of Style for CMOS Online subscribers.

The Windows add-in has a property nothing else here shares: it requires no internet connection at all, so the document never leaves the machine. For legal, government and confidential editing work that is decisive.

Limitations: it does no grammar correction, so it is a complement to the tools above rather than a replacement. The Mac Cloud version has fewer features than the Windows add-in. There is no LaTeX support and no free tier. And the pricing situation is poor — a four-year-old blog post is the only official number.

Best for: professional proofreaders, in-house editorial teams and anyone enforcing a documented house style.

5. Writefull Revise — best for journal manuscripts

Price: not published on any official page — data not available. The plans page loads prices client-side and returns nothing to a direct request. Third-party listings disagree with each other and we are not repeating them. Group licences are self-serve for 2 to 100 people; institutional licences are quote-based (Writefull FAQs) Free tier: exists, with a daily quota of language suggestions. The numeric limit is not published — data not available Platforms: Word add-in, Overleaf (extension and integrated), web apps, publisher API. No Google Docs integration

Writefull’s models were trained on academic text rather than general web prose, and it shows in what the product does. Writefull Revise takes a whole manuscript and returns a .docx with every edit as a Word tracked change. Writefull Cite flags statements that appear to need a citation, at a confidence threshold you set — and Writefull is explicit that this is not plagiarism detection. Premium adds TeXGPT, paraphrasing, style changing, sentence splitting and joining, and table and equation generation.

It is owned outright by Digital Science, which also owns Overleaf, Dimensions, Altmetric and Figshare — hence the unusually good Overleaf support.

Limitations: the pricing opacity is the worst on this page. No Google Docs. The 99.04% accuracy figure attached to Writefull comes from a publisher’s internal review of its API, published by the vendor, and does not describe the consumer product.

Best for: researchers preparing journal submissions, particularly in Overleaf.

6. Trinka — best for LaTeX and technical academic writing

Price: free Basic tier; Premium at approximately $20/month or $80/year, which is the vendor’s own approximate wording on its comparison page because the pricing table renders its price cells empty. Premium Plus pricing: data not available. The Confidential Data plan is listed as “$300 annually / $41.67 per month”, two figures that do not reconcile Free tier: 5,000 words per month, grammar in Lite mode only, no style-guide corrections, Proofread File on up to 4 files but the output is read-only, 5 AI writing requests per month, 1 plagiarism score per month Platforms: web, Word add-in for Windows (lite on macOS), Chrome, Firefox, Edge, Windows desktop app on paid tiers, Moodle plugin (May 2026). No Overleaf integration

Trinka is the only tool here with a dedicated LaTeX proofreader that processes .tex files directly rather than through a browser extension, and paid tiers return editable output carrying tracked changes for both Word and LaTeX. It applies subject-specific style guides — APA, AMA, ACS, AGU and IEEE — runs whole-document consistency and technical checks, and added predatory-journal citation flagging and duplicate-reference detection to its Citation Quality Report on 23 February 2026. An offline Windows checker is available on the Confidential Data tier for work that cannot leave the machine.

Limitations: the published pricing is genuinely unreliable, and a vendor that cannot state its own price consistently is a vendor to check the checkout page of before buying. The free tier’s read-only output makes it a preview rather than a working tier.

Best for: researchers writing in LaTeX, and technical authors working to a named journal style.

7. Paperpal — best for journal submission readiness

Price: Prime $144/year ($12/month billed annually) or $25/month monthly; Pro $348/year ($29/month annually) or $59/month monthly (Paperpal support) Free tier: 200 language suggestions per month, plus limited use of most features Platforms: Word add-in, Chrome and Edge extensions covering Google Docs and Overleaf, web app

Paperpal’s differentiator is the submission-readiness check: it runs an AI review, plagiarism check, reference check, AI-content detection and journal-fit assessment against a manuscript before you submit it, which is a workflow no general proofreader offers. It is built by Cactus Communications, whose Editage brand has been selling human academic editing for two decades, and in November 2025 the publisher-side Preflight product was deployed in the American Physical Society’s editorial workflow. Cactus obtained ISO/IEC 42001:2023 certification for AI management systems in January 2026.

Limitations: whether Paperpal exports Word tracked changes is data not available — it is not documented on any page we could reach, and for a manuscript tool that is a meaningful gap. Its published accuracy comparison against QuillBot and Grammarly is self-run on 20 passages and should carry no weight.

Best for: researchers who want the pre-submission checks and the proofreading in one place.

8. LanguageTool — best for multilingual writing

Price (EUR, inclusive of VAT): €19.90/month; €39.90/quarter (€13.30/month); €59.89/year (€4.90/month); €99.90 for two years (€4.16/month). Teams €56.90 per user per year up to 20 users (LanguageTool help centre, article dated 24 March 2026). A 20% promotion was running on 7 September 2026, on top of these figures. LanguageTool publishes no USD price, and we are not converting one, because VAT treatment differs by market Free tier: 2,000 characters per text field, 3 AI rephrasings per day, limited Picky Mode Premium: 150,000 characters per text field, more than 20,000 additional checks across seven languages, personal and team style guides, team dictionary, text statistics Platforms: Chrome, Edge, Firefox, Safari, Opera; Google Docs, Word, Apple Pages, LibreOffice; Gmail, Outlook (beta), Apple Mail, Thunderbird; macOS and Windows apps; iOS only, no Android

LanguageTool is the pick if you write in more than one language: 30-plus languages against ProWritingAid’s English-only and Grammarly’s English-only correction. Its core rule engine is open source on GitHub, which is unique here and matters if you want to self-host.

The change most comparisons have not caught up with: the browser extension is now Premium-only. LanguageTool states that the extension “is now exclusively available for LanguageTool Premium subscribers”, with free users limited to the web grammar checker and paraphrasing tool (help centre). Any page telling you to install the free extension is out of date.

Limitations: the pricing page has been failing to render prices, which is why the figures above come from the help centre. The vendor also contradicts itself on the Premium character limit — the comparison table says 150,000, the help centre says 100,000. No Android app. Owned by Learneo, the same parent as QuillBot and Scribbr.

Best for: writers working across English, German, French, Spanish, Dutch, Polish or Portuguese.

9. Hemingway Editor Plus — best for readability

Price (USD): free web version; Plus Individual 5K at $25/month or $8.33/month billed annually ($100/year); Plus Individual 10K at $30/month or $12.50/month annually ($150/year); Team 10K at $150 per user per year (Hemingway). The offline Hemingway Editor 3 desktop app is $19.99 one-time per platform and explicitly includes none of the AI features (desktop). Two-week trial, no card required Free tier: readability grade scoring and highlighting of hard sentences, passive voice, adverbs and simpler alternatives, processed locally Platforms: web app; Mac and Windows desktop for the AI-free Classic version. No Word add-in, no Google Docs, no browser extension, no mobile apps

Hemingway does one thing better than anything else here: it tells you how hard your document is to read, lets you set a target reading level, and gives a document review rather than a list of sentence-level flags. Its credit model is unusually fair — one credit equals one sentence rewritten, and grammar fixes cost no credits at all and are unlimited on paid plans. Plus adds .docx, .md and .html import and export.

Limitations: the integration story is the weakest on this page — you work in Hemingway or you do not use it. Note that Hemingway’s own billing FAQ still quotes $10/month, contradicting its live pricing page by two and a half times; the pricing page is the one to trust. The app is now operated by Boondoggle Studio LLC, still by the same founders, Adam and Ben Long.

Best for: writers cutting jargon out of business, policy or marketing prose.

10. Sapling — best for business and support teams

Price: free tier; Pro $25/month or $12/month billed annually; Enterprise from 10 seats at $15 per seat per month (Sapling). One-month free Pro trial, no card. No promotion was showing on 7 September 2026 Free tier: 20 snippets, AI detector at 2,000 characters per check, 5 files per batch, free domains only Platforms: Chrome, Firefox, Edge, Opera, Brave; Word, Outlook and PowerPoint add-ins; Google Docs, Slides and Sheets; Windows and macOS desktop; plus Zendesk, Intercom, Salesforce, HubSpot, ServiceNow, Freshdesk and 30-plus other business systems. SSO via Azure AD, Google OAuth and Okta

Sapling is the only tool here built primarily for teams writing to customers rather than individuals writing documents. It checks grammar, spelling, length, punctuation, tone and formality, readability and sentence variety, across US, UK, Canadian and Australian English plus seven other languages. It is also the most explicit vendor about its architecture, claiming its neural models catch “about 60% more errors than rule-based checkers” (Sapling) — a vendor claim, unverified, but at least a falsifiable one. HIPAA, SOC 2 Type II, PCI, GDPR and CCPA compliance and a self-hosted option round it out.

Limitations: the useful integrations are behind the paid “premium domains” tier — the free plan covers browsers, email and documents only. No mobile app. The pricing page never labels its currency.

Best for: support, sales and success teams standardising written quality across a company.

11. QuillBot — best bundled student toolkit

Price (USD): free tier; Premium $19.95/month, $39.95 per three months, or $99.95/year ($8.33/month) at list — with a 40% promotion showing $5.00/month on 7 September 2026 (QuillBot) Free tier: paraphraser at 125 words per pass in two modes, summariser at 1,200 words, translator at 5,000 characters, AI detector at 1,200 words and 10 scans per day, AI chat at 20 queries per day Premium: 9 paraphrasing modes plus custom modes, plagiarism checking up to 25,000 words per month, tone insights Platforms: Chrome, Edge, Safari; Word add-in; Google Docs; macOS and Windows desktop; iOS and Android

QuillBot’s proofreading is the least distinctive part of a product whose real appeal is breadth: paraphrasing, summarising, translation, citation generation, plagiarism and AI detection in one subscription at student pricing. If you need several of those, the bundle is good value.

Limitations: it has no document-level consistency reporting and no tracked-changes export, which is why it sits here rather than higher. Its own premium page shows two different annual prices — $5.00 on the plan card and $8.33 in the comparison table below it. No independent quantitative accuracy testing of QuillBot exists. Owned by Learneo, same parent as LanguageTool and Scribbr.

Best for: students who want one subscription covering paraphrasing, citations and checking.

12. Ginger — cheapest paid option, with one disqualifying limit

Price: a 50% promotion was running on 7 September 2026. List prices and the promotional prices they fell to: monthly $13.00, promotional $6.50; quarterly $9.99, promotional $4.99 per month ($14.97 total); annual $7.50, promotional $3.75 per month ($45.00 total); two-year $6.00, promotional $3.00 per month ($72.00 total) (Ginger store). Business is 3 users minimum at $9.99 per user per month, though that help article was last updated in 2021 and should be re-checked. 70% student and teacher discount. 7-day money-back guarantee, no free trial of Premium Platforms: Chrome and Edge extensions; Word add-in is Windows-only; macOS and Windows desktop; iOS and Android apps plus an Android keyboard

Ginger is the cheapest way to buy full-sentence contextual correction, translation across 40-plus languages and unlimited rephrasing.

The limitation that decides it: Ginger states that it “is unable to review citations, footnotes, track changes, links or references” and that users must strip them out first (Ginger support). That rules it out for academic writing, legal drafting, and any document that has been through review — which is most documents that need proofreading. Its free-tier limits are also unpublished by design; the terms state they “can be changed at any time without notice”.

Best for: casual writing on a tight budget, where the document has no references.

Also considered: InstaText

Price (EUR): free tier at 5 improvements per day, up to 1,500 characters per edit; InstaText One at €24.99/month monthly or €9.99/month billed €119.88 yearly (InstaText) Platforms: web editor, Word add-in, browser extension covering 20-plus apps including Google Docs and Overleaf

InstaText is a rewriting engine aimed at non-native English speakers, with a personal dictionary that preserves your preferred terminology, and a strict zero-retention privacy claim. It has no tracked-changes export, no document-wide consistency check, no citation checking and no style-guide enforcement, so it is a sentence-level improver rather than a proofreader. Its ownership is not stated anywhere on its site.

The free proofreaders built into what you already own

Before paying for anything, check what your existing subscription already includes.

Three specifics worth knowing:

Microsoft’s Editor browser extension was retired on 31 October 2025 (Microsoft) and its features folded into Edge’s own proofing tools. Microsoft’s Editor marketing page still lists a browser extension in the free-tier column; it is wrong.

Apple Writing Tools has no document-level pass. Its Proofread action works on selected text, invoked per selection, and returns an explanation for each change with Show Original and Revert (Apple). It is excellent for a paragraph and structurally unable to check a 10,000-word document against itself. Apple is replacing the feature with “Write with Siri” in the next OS generation; Bloomberg reported a dedicated grammar checker is being tested, but Apple has not confirmed a continuous proofread-as-you-type mode (MacRumors, 18 May 2026).

Google’s best proofreading feature is not generally available. The “Suggest edits” pass, which reviews a whole document for readability, conciseness, sentence structure, word choice and grammar, is restricted to Gemini EDU Alpha and Workspace Experiments participants (Google). Ordinary Workspace users get Gemini’s quick actions instead, and Business Starter does not get Gemini in Docs at all.

Can you just use ChatGPT, Claude or Gemini?

Yes, with a specific instruction and a specific risk.

The instruction matters more than the model. Türker and Eryiğit (2026) showed that telling a model to make minimal edits rather than to “improve” or “proofread” text moved precision up by roughly 13 points across models. If you paste a document into Claude or ChatGPT and ask it to proofread, you will get a rewrite. Ask it to correct only outright errors of grammar, spelling and punctuation, to change nothing else, and to list what it changed, and you get something closer to proofreading.

The risk is silent meaning change. Labib et al. (2026) measured false insertion rates above 50% for adjectives and adverbs — the model adding modifiers that were not there. Most of those changes read well. Some of them change what the sentence claims, and in a legal, medical or research document that is not a style question.

Where models clearly win is fluency, not correction. Claude Sonnet 4.5 scored 66.09 GLEU on JFLEG, ahead of the specialised systems, and human raters in Coyne et al. (2023) preferred GPT-4’s edits to the benchmark’s own gold references. If your problem is that your prose is stiff rather than incorrect, a general model is the better tool, and best AI for writing covers that use case properly.

The practical stack is to correct with a specialist and polish with a model, in that order, checking the diff. Doing it the other way round means the specialist is checking text you have not read.

Best AI proofreader by use case

Best overall: Grammarly Pro, $12/month annual. The only tool with an independent benchmark score, and it runs everywhere you write. Grammarly

Best for novels and long non-fiction: ProWritingAid Premium, $120/year at list. No word cap, 25-plus structural reports, custom style guide. ProWritingAid

Best for tracked changes on an academic document: Scribbr AI Proofreader, if you write in US English and can accept that the price is unpublished. Writefull Revise is the alternative and has the same pricing problem.

Best for professional editors: PerfectIt. Nothing else checks a document against itself this thoroughly, and the Windows add-in never touches the internet. PerfectIt

Best for LaTeX: Trinka. The only dedicated .tex proofreader with tracked-changes output. Trinka

Best for journal submission: Paperpal Prime, $144/year. Reference checking, AI detection and journal fit in one pre-submission pass. Paperpal

Best for writing in several languages: LanguageTool Premium, €59.89/year. Thirty-plus languages and an open-source core. LanguageTool

Best for plain English: Hemingway Editor Plus, $100/year. Target reading levels and a document-level review, with grammar fixes uncapped. Hemingway

Best for a company: Sapling Enterprise, $15 per seat per month from 10 seats. Consistent tone across support and sales, with SOC 2 and HIPAA. Sapling

Best free option: Grammarly’s free tier for general writing, or LanguageTool’s web checker if you write in more than one language. Both are usable products rather than trials. Note that LanguageTool’s browser extension now requires Premium.

Best value paid option: ProWritingAid lifetime at $399, which pays for itself against the $120/year list price in about three years and four months.

What automated proofreading still gets wrong

It misses structural errors. The last multi-tool academic comparison found no tool exceeding 11% accuracy on sentence-structure errors and none exceeding 25% on semantic errors, against 99% on spelling (Sahu et al., 2020). That study is old, but the shape of the finding has not been contradicted: these tools are near-perfect on orthography and weak on meaning.

It flattens second-language writers’ voices. Liu et al. (May 2026) polished argumentative essays by Chinese B2-level students through four leading models and found “a drastic collapse of dialogic engagement markers, turning negotiated discourse into monologic assertions”. The corrected text was more correct and less the writer’s own. If English is your second language, the same tool that fixes your articles may be removing your hedging, your questions and your stance.

Reference-based scoring penalises valid choices. Labib et al. point out that articles and prepositions have multiple defensible answers, and that writers from languages without article systems get marked wrong for choices that are grammatically fine. This is a property of the benchmarks, and it flows through into products trained against them.

Feedback quality is inconsistent enough to be noticed in the literature. More than half of the 24 studies in Dizon and Gayed’s 2024 systematic review reported problems with Grammarly’s feedback — and Grammarly is the best-evidenced tool in the category.

None of it replaces a reader. Scribbr charges $161 for a human to proofread 8,000 words at a seven-day turnaround, which is a real price for a real service and a reasonable benchmark for what automation is saving you. For a thesis, a contract or a manuscript going to a publisher, the automated pass is the first pass.

Recent changes in this category (2024–2026)

Grammarly became Superhuman. The company acquired Coda (announced 17 December 2024, closed January 2025), raised $1 billion in non-dilutive growth financing from General Catalyst on 29 May 2025 (Grammarly), acquired the email client Superhuman (announced 1 July 2025, terms undisclosed) and renamed itself Superhuman on 29 October 2025. The Grammarly product and domain continue unchanged. Note that the frequently quoted “$825 million” is Superhuman’s 2021 valuation, not a purchase price; the deal price was never disclosed.

Grammarly Premium was retired into Grammarly Pro through 2025, with direct subscribers upgraded at no extra cost.

LanguageTool’s browser extension became Premium-only in 2026, one of the few genuinely consequential free-tier reductions in the category.

Microsoft retired the Editor browser extension on 31 October 2025.

Three of the biggest names share one owner. Learneo now owns QuillBot (acquired 2021), LanguageTool (acquired 5 April 2023) and Scribbr (acquired by Course Hero, March 2022), alongside Course Hero, CliffsNotes, LitCharts and Symbolab. Comparisons that present them as independent alternatives are misleading.

Academic tooling consolidated around publishers. Writefull is wholly owned by Digital Science, which also owns Overleaf. Paperpal’s publisher-side Preflight was deployed in the American Physical Society’s editorial workflow in November 2025. Trinka’s parent, Crimson Interactive, signed manuscript-screening agreements with the Royal Society of Chemistry (September 2025) and IEEE (October 2025). The tool checking your manuscript and the system your publisher screens it with are increasingly the same engine.

Frequently asked questions

What is the best AI proofreader in 2026?

Grammarly Pro, at $12 per month on an annual plan, is the best AI proofreader for most writers in September 2026. It is the only commercial tool in the category with an independently measured accuracy score on a public benchmark — 63.3 F0.5 on CoNLL-2014 in a 2023 study by researchers at the Chinese University of Hong Kong and Tencent AI Lab — and it runs in browsers, Microsoft Office, Google Docs, desktop apps and mobile keyboards. Writers who need Word tracked changes on a whole manuscript should use Scribbr’s AI Proofreader or Writefull Revise instead, and professional editors enforcing a house style should use PerfectIt.

What is the difference between a proofreader and a grammar checker?

A grammar checker works at sentence level and flags errors in the sentence in front of it, such as subject-verb disagreement or a missing comma. A proofreader works at document level and additionally checks the document against itself, catching inconsistencies that are only errors in context — an acronym defined twice, hyphenation that changes between chapters, a citation style applied unevenly, or a spelling variant introduced by a second contributor. Every proofreader contains a grammar checker; most grammar checkers are not proofreaders. PerfectIt is the clearest example of the distinction, because it does document-level consistency checking and no grammar checking at all.

Is there a good free AI proofreader?

Grammarly’s free tier is the best free option for general English writing, covering spelling, basic grammar, tone detection and 100 AI prompts per month with no word limit. LanguageTool’s free web checker is the best free multilingual option at 2,000 characters per text field, though its browser extension now requires a Premium subscription. Hemingway’s free web version gives unlimited readability scoring. ProWritingAid’s free tier caps you at 500 words at a time, Trinka’s at 5,000 words per month with read-only output, and Paperpal’s at 200 language suggestions per month, which makes all three previews rather than usable free products.

Can ChatGPT or Claude proofread my document?

Yes, but you must instruct them to make minimal edits, or they will rewrite rather than correct. Research presented at the BEA 2026 workshop found that switching from an open-ended proofreading instruction to an explicit minimal-edit instruction raised GPT-4.1’s precision on CoNLL-2014 from 57.26 to 70.37, while its recall fell by an equivalent amount. The risk with general models is silent meaning change: a 2026 study measured false insertion rates above 50% for adjectives and adverbs, meaning the model adds modifiers the writer never wrote. For legal, medical or research documents, use a specialist proofreader first and a general model only for fluency afterwards, checking the difference.

How accurate are AI proofreaders?

No vendor publishes precision or recall figures for its production proofreader, so there is no honest single answer. The only independent measurement of a commercial tool on a public benchmark found Grammarly at 67.3% precision and 51.1% recall on 100 CoNLL-2014 sentences in 2023 — accurate when it speaks, and silent about roughly half the errors present. An older five-tool academic comparison found the best performer at 44.4% overall accuracy, with 99% on spelling but under 11% on sentence-structure errors. Treat automated proofreading as very strong on spelling and punctuation, moderate on grammar, and weak on meaning and structure.

Which AI proofreader gives tracked changes in Microsoft Word?

Scribbr’s AI Proofreader, Writefull Revise and Trinka’s paid tiers all return a Word document with every edit recorded as a tracked change that you accept or reject individually. PerfectIt works natively inside Word, so its changes appear in Word’s own review workflow. Grammarly, ProWritingAid, LanguageTool, QuillBot, Hemingway, Sapling and Ginger do not offer tracked-changes export, and Ginger cannot process a document that already contains tracked changes at all.

Is Grammarly still called Grammarly?

Yes. The company renamed itself Superhuman on 29 October 2025, after acquiring the email client of that name in July 2025 and the document platform Coda in January 2025, but Grammarly remains the name of the writing product. Grammarly.com still operates, still sells the Free, Pro and Enterprise plans, and the site footer now reads “Superhuman Platform”. Enterprise customers are the exception: Grammarly is delivered to them through Superhuman Go, the company’s cross-application AI assistant.

What is the best AI proofreader for academic papers?

It depends on your format. For a Word manuscript where you need tracked changes and write in US English, use Scribbr’s AI Proofreader. For a journal submission, Paperpal Prime at $144 a year adds reference checking, AI-content detection and journal-fit assessment to the proofreading pass. For LaTeX, Trinka is the only tool with a dedicated .tex proofreader and subject-specific style guides covering APA, AMA, ACS, AGU and IEEE. Writefull Revise is the strongest option if you work in Overleaf, though it does not publish its prices.

Do AI proofreaders work for British and Australian English?

Most do, but check before you buy. ProWritingAid supports General, British, US, Australian and Canadian English; Sapling supports US, UK, Canadian and Australian; LanguageTool supports British and American English among 30-plus languages. Scribbr’s AI Proofreader applies US English conventions only, which rules it out for a UK or Australian submission, although its human proofreading service does offer British and Australian English. Where a tool does not state its supported variants, assume US English.

Will using an AI proofreader make my writing flagged as AI-generated?

Correcting spelling, grammar and punctuation does not meaningfully change the statistical signals AI detectors look for, so a proofreading pass is not what gets a document flagged. Accepting large-scale rewrites is a different matter, because rewriting replaces your sentence structures with the model’s. The practical line is that a tool suggesting a comma is not a provenance question and a tool rewriting your paragraph is. Institutional policies vary widely and some prohibit any AI assistance regardless of scope, so check your institution’s rules rather than the tool’s. Our best AI detector page covers how detection actually works.

Can an AI proofreader replace a human proofreader?

Not for anything consequential. Automated tools are near-perfect on spelling, strong on punctuation and mechanical grammar, and weak on structure, meaning and argument — the same study that put a tool at 99% on spelling put every tool below 11% on sentence-structure errors. A human proofreader also catches the errors that are only visible with context: a claim that contradicts one made forty pages earlier, a figure reference pointing at the wrong figure, a tone that is wrong for the reader. Scribbr charges from $0.017 per word plus a $25 setup fee, or $161 for 8,000 words at a seven-day turnaround, which is a reasonable benchmark for the cost of that judgement.

How to choose in September 2026

Start from the format, not the brand. If you need tracked changes, your realistic choices are Scribbr, Writefull Revise, Trinka or PerfectIt, and everything else on this page is disqualified regardless of price. If you write in LaTeX, it is Trinka or Writefull. If you enforce a house style, it is PerfectIt. If you write in more than one language, it is LanguageTool.

If none of those apply — and for most writers none of them do — buy Grammarly Pro at $12 a month, use the free tier first to see whether you need Pro at all, and add ProWritingAid only if you are editing manuscripts rather than documents.

Two things to hold onto. First, the prices on this page move: four of twelve vendors were discounting on 7 September 2026, and three contradict themselves on their own websites. Check the checkout page, not the marketing page. Second, nobody in this category will tell you how accurate their product is, and the independent evidence that exists is thin, dated and mostly about one vendor. Anyone quoting you a precision figure for a proofreading tool is quoting something they did not measure.