Grammarly vs QuillBot: Which to Pay For in 2026

A detector score is a guess. A writing history is evidence.

Picture the case every writing instructor now sees some version of. You write an essay yourself, then run two stiff paragraphs through a paraphraser to make them sound smarter, and the finished document comes back flagged as likely AI. Unless something recorded the hours you spent typing, the only thing anyone can look at is the percentage.

That is why I would not frame this as a grammar contest. The Grammarly vs QuillBot comparisons ranking for this keyword run from about 2,800 to 4,000 words, and they agree on the basics: Grammarly is a grammar and tone tool, QuillBot is a paraphraser with a grammar checker attached, QuillBot is cheaper, and plenty of people use both. All correct. None of the three I read mentions Grammarly's Authorship feature or what Turnitin now says about paraphrased text, and for anyone whose writing gets checked by somebody else, that is the part that matters.

If you want the wider field, our AI writing tools roundup covers the drafting tools, and our guide to AI tools for writers and authors explains where Grammarly fits next to ProWritingAid and Hemingway.

What each one actually is

Grammarly is an editor that sits on top of wherever you already write: the browser, Google Docs, Word, email. It underlines mistakes, tells you how your tone reads, and on the paid plan rewrites whole sentences with a click. Since late 2025 it has been part of Superhuman's suite, next to Superhuman Mail and Coda. The standalone Grammarly plans are still sold on their own.

QuillBot is a rewriter. You paste a passage in, pick a mode, and it gives you the same meaning in different words, with a synonym slider for how far it should stray from your original. Around that core it has added a summarizer, a translator, a citation generator, a plagiarism checker on the paid plan, and its own AI detector.

Grammarly fixes your sentences. QuillBot replaces them.

The short answer

	Grammarly	QuillBot
Built for	Correcting and polishing what you wrote	Rewording a passage you already have
Free plan	Unlimited spelling and grammar checks, tone detection, 100 AI prompts a month	Paraphrases up to 125 words at a time, in 2 modes; summarizer up to 1,200 words
Paid plan	Pro: $12 a month billed yearly ($144), $30 month to month	Premium: $99.95 a year ($8.33 a month), $19.95 month to month
What paying adds	Full-sentence rewrites, plagiarism and AI-text detection, 2,000 AI prompts a month	Unlimited paraphrasing, 9+ modes, 6,000-word summaries, 25,000 words of plagiarism checks a month
Trial or refund	7-day free trial of Pro	3-day money-back guarantee
Records how you wrote	Yes, Authorship, on every plan including free	No

Prices are from grammarly.com and QuillBot's published plans as of October 2026.

Grammarly: the one you leave switched on

The reason to use Grammarly is that you stop noticing it. It catches the doubled word and the wrong "its" in an email you were about to send, and it does that in every text box you type into without you opening anything. The free plan is the more generous of the two by a distance. Unlimited basic checks is the whole job for a lot of people.

Pro earns its price if you write for a living or write in a second language. The sentence rewrites are good at untangling a 50-word sentence into two readable ones.

Our writers guide makes a fair complaint, though, and I have hit it myself: the rewrites pull everything toward the same neutral voice. Accept every suggestion on a personal essay and it will read like a press release. Treat Pro's rewrites as offers, and turn down most of them.

The price trap is billing. $12 a month assumes you pay for the year up front. Month to month is $30, which is more than double, and more than QuillBot's monthly price too.

QuillBot: the one you open on purpose

QuillBot is a tool you go to. That is its strength. When a paragraph is correct but stiff, or you need the same product description in a shorter and a more formal version, the paraphraser gets you there faster than rewriting by hand, and the freeze-words option keeps it from touching a brand name or a technical term.

The free plan is a demo. At 125 words a pass and two modes, you can rework a paragraph, not a page. Premium at $99.95 a year is cheap for what it does, and the 3-day refund window is short enough that you should test it on real work the day you buy it.

Its grammar checker is fine. If correctness is your main problem, though, you are paying for the wrong tool.

The part nobody mentions: the record of how you wrote

Here is the angle the other comparisons skip, and it is where students and freelancers get burned.

Turnitin, which many universities run, says its AI-writing detection now looks for AI-paraphrased text from word spinners and paraphrasing tools, and it names QuillBot. Independent tests disagree about how well that works. Turnitin itself warns that its model can misidentify human writing and should not be the only basis for action against a student. QuillBot, for its part, says its paraphraser is not meant to get around detection. The detection is unreliable in both directions, and that is exactly the problem. If a flag can land on honest work, you need a way to show the work.

That is what Grammarly Authorship does. Switch it on in Google Docs (through the Chrome or Edge extension), in the Word desktop app, or in Grammarly's own editor, and it labels every piece of text by where it came from: typed by you, pasted from a website, pasted from an AI tool like ChatGPT or Claude, or edited with Grammarly's own suggestions. You can replay the document from the first keystroke and share a color-coded report. It is on the free plan. It needs clipboard access to tell an AI paste from a Wikipedia paste, and Grammarly's help center says Word history is only reliable up to 20 pages.

A paraphraser works against that record. Text rewritten in QuillBot and pasted back arrives as pasted text, and the record of you typing the original is gone from that passage.

My rules now, for anything someone else will grade or check:

1. Turn on Authorship before you write the first sentence. It cannot reconstruct a document after the fact.
2. Draft in Google Docs or Word, never in a paraphraser window.
3. If you use QuillBot on a passage, keep the original version and note what you changed. A dated copy of your own sentences beats any detector score.
4. Never paraphrase someone else's text to avoid a citation. Cite it.

Rule 3 feels like overkill until the day you need it.

Which one to pay for

Pay for Grammarly Pro if you write all day in a browser or in a second language. If your main worry is work that gets checked, the free plan plus Authorship already covers the part that matters. Try free first.

Pay for QuillBot Premium if your real job is rewording, like turning one product description into short and formal versions, or boiling a long report down to a page. At $99.95 a year it is cheap enough to keep alongside Grammarly's free plan, and that pairing is the one I would recommend to most people who need both.

If you are a student, start with free Grammarly and Authorship switched on. Our AI tools for students roundup covers the research and note-taking side.

Frequently Asked Questions

Is Grammarly better than QuillBot?

They do different jobs. Grammarly corrects and polishes text you wrote, in every app you type into, and its free plan is more generous. QuillBot rewords a passage you already have, and its paid plan is cheaper. For grammar and tone, Grammarly is better. For paraphrasing, QuillBot is.

How much do Grammarly and QuillBot cost in 2026?

Grammarly Pro costs $12 a month billed yearly ($144) or $30 month to month, with a 7-day free trial. QuillBot Premium costs $99.95 a year, which works out to $8.33 a month, or $19.95 month to month, with a 3-day money-back guarantee.

Can Turnitin detect QuillBot?

Turnitin says its AI-writing detection looks for AI-paraphrased text and names QuillBot among the tools it targets. Independent tests have produced mixed results, and Turnitin warns that its model can misidentify writing and should not be the only basis for action.

What is Grammarly Authorship?

Authorship tracks how a document was written in Google Docs, Microsoft Word or Grammarly's editor. It labels text as typed, pasted from a website, pasted from an AI tool, or edited with Grammarly, and produces a shareable report with a replay of the writing process. It is included on Grammarly's free plan.

What is the QuillBot free plan limit?

QuillBot's free plan paraphrases up to 125 words at a time in two modes, Standard and Fluency, and summarizes up to 1,200 words. Premium removes the paraphrasing limit, unlocks 9+ modes and adds a plagiarism checker with 25,000 words a month.