How it scores
What we love (and don't)
// PROS
- Grammar checker is free and runs unlimited checks at no cost
- Free paraphraser works with no account required; Standard and Fluency modes available
- Nine predefined paraphrase modes in Premium, plus unlimited Custom modes you build yourself
- Plagiarism checker covers 25,000 words per month in 100+ languages
- Runs everywhere: Chrome, Edge, Word, macOS, Windows, iOS, Android
- One subscription covers the full suite: paraphraser, grammar, plagiarism, AI detector, humanizer, summarizer, citations
- Translate text into 40+ languages on Premium
// CONS
- Free paraphraser caps at 125 words per pass. Anything longer requires Premium.
- Plagiarism checker is Premium-only. No free quota at all.
- Free plan locks you to Standard and Fluency modes. The seven useful Premium modes cost money.
- AI Detector access is limited on the free plan
- QuillBot's pricing page does not display a monthly-billing price; only the annual rate ($8.33/mo) is shown
The QuillBot grammar checker runs unlimited checks at no cost, and its page says no sign-up is required. I think that is the part of QuillBot most writers miss.
The paraphraser does have a paywall. The free plan caps at 125 words per pass and two modes. For a quick rewrite, that is enough. For anything involving a full paragraph, an email draft, or academic content that needs rephrasing and plagiarism checking in the same session, it is not.
QuillBot says it is trusted by over 35 million writers. That number explains the brand, not what the tool does.
What QuillBot actually is
QuillBot is a writing suite from Learneo, Inc., the company that also owns LanguageTool and Scribbr. It started in a college dorm in 2017, went viral on Reddit, entered UIUC’s iVenture Accelerator, reached one million users in 2019, and became part of Learneo (then Course Hero) in 2021. QuillBot says that under CEO Andrew Grauer it has expanded beyond writing with audio, image, and search tools.
The tools: Paraphraser, Grammar Checker, AI Detector, Plagiarism Checker, AI Humanizer, AI Chat, AI Image Generator, Translate, Summarizer, and Citation Generator.
I expect most writers will lean on one or two. The pitch is that Premium gives you all of them from the same account.
The paraphraser
I think this is still the main reason people open QuillBot. Paste text, choose a mode, click Paraphrase. The tool rephrases sentences without changing their meaning.
The free plan gives you two modes. Standard rewrites vocabulary and word order. Fluency improves clarity and readability. Both work on input up to 125 words.
Premium adds seven more:
- Formal: rephrases in a more sophisticated register
- Simple: brings complex text down to plain language
- Creative: introduces more varied phrasing
- Academic: shifts tone to a technical, scholarly style
- Expand: lengthens the output
- Shorten: condenses
- Humanize: rewrites in a more human, authentic voice
Custom mode lets you describe the style you want in plain text. Want the output to match a specific brand voice or persona? You write the description; QuillBot attempts to match it. That is a Premium-only feature, and the plan table says you can create unlimited Custom modes.
The Synonym Slider adjusts how aggressively the tool substitutes vocabulary. Left side produces minimal changes; right side produces more creative output with heavier word swaps.
The Premium plan table says the paraphraser works in 23 languages; the paraphrasing tool page says 20+.
The grammar checker
I think the grammar checker is the most underrated tool in the suite. It runs unlimited checks at no cost, and the page says no sign-up is required. It fixes grammar, spelling, and punctuation and adds AI-powered clarity suggestions. Available in 6+ languages.
In my view it is the best free offer in the suite.
The limitation is depth. Free grammar checking handles basic corrections. Advanced writing suggestions and Tone insights are Premium features. For many use cases, I think the basic check is enough.
Plagiarism checker
The plagiarism checker requires Premium. No free quota.
On Premium, you get 25,000 words per month. It scans in 100+ languages and returns a report with potential plagiarism, source links, and missing citations. The plagiarism checker page notes that you can buy additional words beyond the monthly allotment.
For academic writers, this is the strongest single reason to pay. Submitting a paper with accidental plagiarism from an earlier draft is a real risk, and I would expect 25,000 words per month to cover most coursework.
For content writers and marketers, the value depends on volume. If you produce original work and are not quoting from sources, the checker is less essential.
The rest of the suite
AI Humanizer. Takes AI-generated text and rewrites it to read more naturally. Free plan allows up to 125 words with limited usage. Premium gives full access with history and insights. Supports Spanish, German, French, Portuguese, and four dialects of English (US, UK, AU, CA).
Summarizer. Free: up to 1,200 words. Premium: up to 6,000 words, with custom summary options.
AI Detector. Limited access on free; full access on Premium. I would pair it with the Humanizer to check how AI-generated a draft reads.
Translate. Renders text into 40+ languages on Premium.
Citation Generator, AI Chat, AI Image Generator. All available on Premium. The image generator has usage limits even on Premium.
Pricing
QuillBot Premium is $8.33 per month billed annually. The annual plan carries a 58% discount. The plagiarism checker page references “1 of 3 Premium plans,” and only the annual price is displayed on the pricing page; check quillbot.com/premium for current monthly rates.
The annual math: $8.33 × 12 = $99.96 per year.
For teams, there is a separate Team plan with centralized billing, user management, usage metrics, and data controls.
The paraphraser and grammar checker pages both say no sign-up is required, so you can try them before creating an account.
How it compares
For pure grammar and style editing, Grammarly is the stronger option in my view. QuillBot’s grammar checker works, but grammar is a side tool here, not the core product.
For AI writing assistance, Jasper is the one I would look at first if you are generating content from scratch. If you are reworking existing text, QuillBot’s paraphraser is the more focused tool.
QuillBot sits cleanly in the category of rewriting and academic integrity tools. That position is different enough from both competitors that the choice is usually clear by use case. Writers who need to rewrite, check for plagiarism, and humanize AI drafts in one place should evaluate QuillBot over trying to piece together separate tools. The best AI writing tools roundup covers the broader category for anyone still choosing.
Who should pay
The free plan is worth bookmarking for anyone who rewrites text occasionally. The grammar checker alone is worth a bookmark.
Premium at $8.33 per month annual makes sense for:
- Students writing academic papers who need plagiarism checking
- Content writers who rephrase text frequently and need more than 125 words per pass
- Writers working in multiple languages
- Anyone producing AI-assisted drafts who needs the Humanizer and AI Detector together
Skip Premium if you only need occasional sentence rewrites. The free plan handles that.