QuillBot

QuillBot is an AI writing toolkit best known for its paraphraser. It is part of Learneo, the company formerly called Course Hero.

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Owner

Learneo, Inc. (formerly Course Hero)

Founded

2017

Headquarters

Chicago, Illinois, United States

Quick answer: QuillBot is an AI writing toolkit best known for its paraphraser, used largely by students. It also offers a grammar checker, summariser, translator, citation generator, AI chat, a plagiarism checker, an AI Detector and an AI Humanizer. It is part of Learneo, the company formerly called Course Hero, which also owns Scribbr and LanguageTool. Most tools have a free tier with word limits, and Premium costs $8.33 a month on an annual plan.

What QuillBot does

QuillBot rewrites, checks and tidies up text. You paste in a paragraph and it rephrases it, fixes the grammar, shortens it, translates it or turns it into a citation. It started as a paraphrasing tool and has grown into a wider set of writing tools for students and everyday writers.

It runs in the browser and has extensions and apps for Chrome, Edge, Safari, Microsoft Word, macOS, Windows, iOS and Android. QuillBot says it is trusted by 35 million people, and its Chrome extension lists 6 million users.

Who owns and runs it

QuillBot was founded by Rohan Gupta, Anil Jason and David Silin, who started it while studying at the University of Illinois Urbana-Champaign. Course Hero later bought it, and Course Hero’s parent company has since become Learneo. QuillBot’s site footer reads “a Learneo, Inc. business”, and the Chrome Web Store lists the publisher as QuillBot (Course Hero), LLC in Chicago.

Learneo’s list of businesses puts QuillBot alongside Course Hero (including CliffsNotes), Scribbr, LanguageTool, LitCharts and Symbolab. QuillBot also powers Scribbr’s free grammar checker and paraphrasing tool.

What it offers

It also offers an AI image generator, an AI image detector, a presentation maker, a website builder, a resume builder, PDF chat and text-to-speech. Free-tier limits come from QuillBot’s help centre.

QuillBot Paraphraser

The paraphraser is QuillBot’s original product. You paste text in, pick a mode (such as Standard or Fluency) and it rewrites the passage while keeping the meaning. Free users get two modes and 125 words at a time. Premium removes the word limit and adds the remaining modes, side-by-side mode comparison and a history.

For other paraphrasers, see best AI paraphrasing tools.

QuillBot AI Detector

The AI Detector estimates how much of a piece of text was written by AI. It needs no sign-up.

What it reports. The detector splits a text into three shares: AI-generated, AI-refined (human writing that has been polished or edited with AI) and human-written. It highlights the sentences behind the score, and for flagged sentences it gives a low, medium or high explanation. The free version shows one explanation per scan, and exporting a report needs Premium (QuillBot).

Limits. Free use covers up to 1,200 words per scan, with a cap on scans per day. Premium is unlimited.

How QuillBot describes it. QuillBot says its detector “effectively differentiates between text produced by AI and by humans” and can spot text that has been “partially refined, edited, or enhanced using AI writing tools”. On detection in general, QuillBot says detectors “do not provide definitive proof” and “may produce false positives or false negatives” (QuillBot), and that they work best “as one signal among many, not as a sole judge” (QuillBot).

For how detectors work in general, see how AI detectors work. For independent testing across detectors, see best AI detector.

QuillBot AI Humanizer

The AI Humanizer rewrites text “so it sounds more natural and human-generated, rather than created by an LLM”, in QuillBot’s own words. Free use is limited, and the Paraphraser also has a Premium-only Humanize mode. On Premium the humanizer connects to the AI Detector to show the text’s “human score”.

QuillBot’s guidance to students is to “follow your instructor and/or school’s policies” and to disclose AI use where that’s required.

What it costs

QuillBot Premium unlocks every tool at once. List prices are $19.95 a month, $39.95 every three months, or $99.95 a year, which works out to $8.33 a month. Prices vary by region, and QuillBot also runs discounts.

Most tools are usable for free within the limits above. The Plagiarism Checker is Premium only.

How it’s used

QuillBot’s tools are used largely by students and everyday writers, to reword a paragraph, fix grammar, summarise a reading, format a citation or translate a passage. One free account covers all of these tools. QuillBot also offers the AI Detector to teachers as a first check on submitted work.

Frequently asked questions

Is QuillBot free?

Mostly, yes. The paraphraser, grammar checker, summariser, translator, citation generator, AI chat and AI Detector all have free versions with word or usage limits. The Plagiarism Checker needs Premium, which costs $8.33 a month on an annual plan.

How does QuillBot describe its AI Detector’s accuracy?

QuillBot says the detector “effectively differentiates between text produced by AI and by humans”. It also says no detector provides definitive proof, and that results work best as one signal among many. For independent testing across detectors, see best AI detector.

Who owns QuillBot?

Learneo, the company formerly called Course Hero. Learneo also owns Scribbr, LanguageTool, CliffsNotes, LitCharts and Symbolab.

What does QuillBot Premium include?

Premium removes the free word and usage limits, adds the remaining paraphrasing modes and the Humanize mode, and unlocks the Plagiarism Checker. It costs $19.95 a month, $39.95 every three months or $99.95 a year.

Is QuillBot the same as Scribbr?

No. They are separate businesses with the same owner, Learneo. QuillBot powers Scribbr’s free grammar checker and paraphrasing tool.