QuillBot

QuillBot is the most widely used AI paraphrasing and rewriting tool in the world, with over 200 million registered users as of 2025. Founded in 2017 and acquired by Course Hero in 2021, it has become the dominant tool for students, academics, ESL learners, and content writers who need to rephrase, summarize, or improve existing text. Its Premium plan at $9.95/month (annual billing) is one of the cheapest paid AI writing tools available, which largely explains the scale of its user base.

The core product is a paraphraser with eight modes — Standard, Fluency, Formal, Academic, Simple, Creative, Expand, and Shorten — that rewrite selected text with varying levels of transformation. Alongside the paraphraser, QuillBot includes a grammar checker, summarizer, plagiarism checker (paid), citation generator, and translator. The full-suite positioning makes it the default toolkit for students writing essays and researchers paraphrasing sources.

QuillBot is not a content generation tool. It does not write from prompts. It works only on existing text. That narrow focus, combined with a very low price and a large free tier, has made it the dominant player in paraphrasing specifically — a market with persistent demand from students and ESL users that general-purpose AI tools do not fully serve.

What It Does

QuillBot takes input text and produces paraphrased alternatives in the selected mode. Users paste or type text, choose a mode and synonym frequency (how aggressively it swaps words), and receive a rewritten version with changes highlighted. The word flipper controls let users selectively accept or revert individual changes. The grammar checker operates like a simplified Grammarly. The summarizer condenses documents into bullet points or paragraphs. The plagiarism checker (paid) scans against web sources. The citation generator produces properly formatted academic citations from URLs or DOIs.

Who It’s For

• Students paraphrasing sources for essays, avoiding accidental plagiarism, and improving draft quality
• ESL learners and non-native English speakers converting grammatically correct but stilted phrasing to natural English
• Academic writers paraphrasing research sources and generating citations
• Content writers rewriting existing content for new platforms or slightly different audiences
• Bloggers and SEO writers creating content variations — though this use case is ethically and practically contested

QuillBot is the go-to tool for anyone who starts from existing text and needs to express the same ideas differently. It is not designed for users who need to generate content from scratch.

Pricing

Pricing verified at quillbot.com/pricing as of 2026-04-14. Monthly billing available at higher rates; annual billing produces the $9.95/mo rate.

Key Features

• Eight paraphrase modes: Standard, Fluency, Formal, Academic, Simple, Creative, Expand, and Shorten. The Academic and Formal modes are particularly useful for professional and academic writing contexts.
• Synonym slider: Adjusts how aggressively QuillBot swaps vocabulary. Low settings preserve original phrasing with minimal changes; high settings produce more thorough rewrites. Granular control distinguishes it from simpler paraphrasers.
• Word flipper: Click any highlighted replacement to cycle through alternative word choices. Allows fine-grained acceptance or rejection of individual changes.
• Grammar checker: Catches grammar, spelling, and punctuation errors. Less sophisticated than Grammarly but covers the basics and integrates directly with the paraphrase workflow.
• Summarizer: Produces key-point bullet summaries or paragraph summaries of long texts. Useful for research workflows where reading the full source is impractical.
• Plagiarism checker (Premium): Scans text against web sources. 20 pages/month on Premium. Helpful for students verifying paraphrased content before submission.
• Citation generator: Creates APA, MLA, Chicago, and other citation formats from URLs, DOIs, or ISBN numbers. Genuinely useful and frequently overlooked feature.
• Chrome extension and Google Docs integration: Access QuillBot without switching tabs.
• 200M+ user community and brand trust: At scale, QuillBot benefits from being the default known option for students — network effects in the sense that it’s what writing guides and teachers reference.

Limitations

• Free tier 125-word limit is genuinely restrictive: Most paragraphs exceed 125 words. Free users hit the limit on almost every use. This is intentional — the free tier functions primarily as a demo.
• Not a content generation tool: QuillBot cannot write from a blank prompt. Users who need generation and paraphrasing need a second tool. This is a real gap compared to ChatGPT or Jasper.
• Paraphrasing at high settings can degrade meaning: Aggressive synonym swapping sometimes changes the meaning of technical or precise sentences. Users must review output carefully, especially in academic and legal contexts.
• Plagiarism checker limited to 20 pages/month on Premium: For students with heavy research workloads, this limit is hit quickly. Dedicated plagiarism tools like Turnitin provide more comprehensive coverage.
• Owned by Course Hero — education company, not pure AI company: Course Hero’s acquisition makes strategic product investment dependent on an education-focused parent company’s priorities. The product is maintained but not aggressively developing new AI capabilities.
• Ethical concerns in academic use: Many universities flag QuillBot-paraphrased text as academic dishonesty, and AI detection tools are increasingly trained to identify it. Users should be aware of their institution’s policies.

Bottom Line

QuillBot Premium at $9.95/month (annual) is one of the best value propositions in AI writing tools. For students, ESL users, and content writers who regularly work from existing text, the full suite — paraphraser, grammar checker, summarizer, plagiarism checker, citation generator — at under $10/month is genuinely hard to beat on price. The 200M user base reflects real utility, not just marketing.

The limitation to accept is that QuillBot is a single-function tool at its core. It paraphrases; it does not generate. For users who need both, pairing QuillBot Premium ($9.95/mo) with ChatGPT Free or Claude Free covers most writing needs at low total cost.

Best Alternatives

FAQ

Is QuillBot free? Yes. The free plan allows paraphrasing up to 125 words at a time using Standard and Fluency modes, plus a basic summarizer. The limit resets per use (not daily). Premium at $9.95/month (annual billing) removes word limits and unlocks all eight modes, the plagiarism checker, and faster processing.

Can universities detect QuillBot paraphrasing? AI detection tools and plagiarism checkers are increasingly trained to identify AI-paraphrased text, including QuillBot output. Many universities classify use of AI paraphrasing tools as academic dishonesty under their academic integrity policies. Institutional policies vary. Users should check their institution’s rules before submitting AI-paraphrased work.

How is QuillBot different from Grammarly? QuillBot rewrites text to express the same ideas differently (paraphrasing). Grammarly corrects grammar, spelling, and style errors in existing text. Grammarly improves how text is written; QuillBot changes what words are used to say it. They serve different primary functions and are often used together.

Who owns QuillBot? QuillBot was founded in 2017 and acquired by Course Hero, the education technology company, in 2021. Course Hero provides study tools, textbook solutions, and tutoring services. QuillBot operates as a distinct product within the Course Hero portfolio.

Sources

• Official website
• Pricing page