The best AI grammar checkers in 2026

As of October 2026, QuillBot is our top-rated AI grammar checker, at 4.3 out of 5, for free grammar checks with a paraphraser built in. Grammarly shares that score and is our pick for checks across most apps, and LanguageTool for writing in other languages.

By the Max Productive AI editorial team. Updated .

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Our picks for October 2026

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  1. Best overall

    QuillBot

    Our rating: 4.3 / 5

    Free grammar checks. Premium $8.33 a month, billed yearly.

    Visit QuillBotRead review of QuillBot

  2. Best for checks across most apps

    Grammarly

    Our rating: 4.3 / 5

    Works almost everywhere you type. Pro $12 a month, billed yearly.

  3. Best for other languages

    LanguageTool

    Our rating: 4.2 / 5

    Checks 30+ languages. Premium $5.83 a month, billed yearly.

  4. Best for books and long-form

    ProWritingAid

    Our rating: 4.2 / 5

    Editing reports for long documents. Premium $10 a month, billed yearly.

All AI grammar checkers, ranked

Ordered by our rating. Prices: lowest paid plan on annual billing, per month for one user unless the row says otherwise, checked on 18 October 2026. This article contains affiliate links.

  1. QuillBot Reviewed

    Best for free grammar checks plus a paraphraser and citations

    Note: tone insights and advanced suggestions need Premium

    Free plan paraphrase up to 125 words

    From $8.33 a month (Premium)

    Our rating: 4.3 / 5

    Read review of QuillBotVisit site of QuillBot

  2. Grammarly Reviewed

    Best for real-time grammar and tone checks in almost every app

    Note: tone changes and full rewrites need Pro

    Free plan 100 AI prompts a month

    From $12 a month (Pro)

    Our rating: 4.3 / 5

    Read review of GrammarlyVisit site of Grammarly

  3. LanguageTool

    Best for checking writing in more than one language

    Note: Premium's extra checks cover seven of its languages

    Free plan 2,000 characters per check

    From $5.83 a month (Premium)

    Our rating: 4.2 / 5

    Visit site of LanguageTool

  4. ProWritingAid

    Best for novelists and long-form writers who want editing reports

    Note: English only

    Free plan suggestions on 500 words at a time

    From $10 a month (Premium)

    Our rating: 4.2 / 5

    Visit site of ProWritingAid

  5. Paraphraser.io Reviewed

    Best for free grammar checks on uploaded files

    Note: we found no browser extension or Word add-in

    Free plan grammar checker and paraphraser

    From $47.52 a year (Diamond)

    Our rating: 3.9 / 5

    Read review of Paraphraser.ioVisit site of Paraphraser.io

Our picks in detail

What each pick does well, where it falls short and who should skip it. Strengths and limits come from our reviews where we have one and from each vendor's own pages, checked on 18 October 2026.

  1. Best overall: QuillBot

    Our rating: 4.3 / 5

    QuillBot checks grammar, spelling and punctuation for free, and keeps a paraphraser, summarizer and citation generator in the same account. It runs in Chrome, Edge, Safari and Word, and as apps for Windows, Mac and phones.

    Strengths

    • Grammar, spelling and punctuation checks are free
    • Paraphraser, summarizer and citations in one place
    • Apps for Chrome, Word, Windows, Mac and phones

    Limits

    • Tone insights and advanced suggestions need Premium
    • Free paraphrasing stops at 125 words
    • Refund terms vary by region; check before buying

    Skip it if you want tone and style feedback across most of the apps you write in. Grammarly goes further there.

    Go deeper: QuillBot Mobile Review

    Free plan. Paid from $8.33 a month (Premium).

    Read review of QuillBotVisit QuillBot

  2. Best for checks across most apps: Grammarly

    Our rating: 4.3 / 5

    Grammarly checks grammar, spelling and clarity as you type, in browsers, desktop apps, Google Docs and on your phone's keyboard. Pro adds tone changes, full-sentence rewrites and plagiarism checks.

    Strengths

    • Real-time checks in browsers, desktop apps and phones
    • Grammar and spelling in 20+ languages, 17 in beta
    • Pro adds tone, rewrites and plagiarism checks

    Limits

    • Pro is $30 a month on monthly billing
    • Other languages get grammar and spelling only
    • Free plan caps AI prompts at 100 a month

    Skip it if you mostly write in a language other than English. LanguageTool checks more than 30 languages.

    Free plan. Paid from $12 a month (Pro).

    Read review of GrammarlyVisit Grammarly

  3. Best for other languages: LanguageTool

    Our rating: 4.2 / 5

    LanguageTool checks grammar, spelling and style in more than 30 languages, including German, French, Spanish, Dutch and Portuguese. It works in five browsers, Word, Google Docs and Gmail, and as apps for Mac, Windows and iOS.

    Strengths

    • Checks in 30+ languages
    • Add-ons for Word, Google Docs, Gmail and browsers
    • Teams plan with a shared style guide and dictionary

    Limits

    • Free plan checks 2,000 characters at a time
    • Free plan allows 3 AI rephrasings a day
    • Premium's extra checks cover seven languages

    Skip it if you write only in English and want tone help across most apps. Grammarly fits better.

    Free plan. Paid from $5.83 a month (Premium).

    Visit LanguageTool

  4. Best for books and long-form: ProWritingAid

    Our rating: 4.2 / 5

    ProWritingAid pairs a grammar checker with line-editing reports and chapter feedback for long documents such as novels. Premium makes line-editing reports unlimited and handles documents of any length.

    Strengths

    • Line-editing reports and chapter critiques
    • Premium handles documents of any length
    • Lifetime plan available, from $399

    Limits

    • English only
    • Free plan checks 500 words at a time
    • One Chapter Critique a day on Premium

    Skip it if you mainly write short emails and messages across many apps. QuillBot or Grammarly suit that better.

    Free plan. Paid from $10 a month (Premium).

    Visit ProWritingAid

How to choose an AI grammar checker

Start from what you write and where you write it, then compare price. Every tool here has a free plan, so try it on your own text before you pay.

  • You want free, everyday grammar checks

    QuillBot checks grammar, spelling and punctuation for free. Premium, at $8.33 a month billed yearly, adds tone insights and suggestions on passive voice and repeated phrases. Grammarly's free plan also fixes basic errors and includes 100 AI prompts a month.

  • You write in many apps and care about tone

    Grammarly checks your writing as you type in browsers, Windows and Mac apps, Google Docs and on your phone. Its Pro plan adds tone changes, full-sentence rewrites and plagiarism checks, at $12 a month billed yearly or $30 billed monthly.

  • You write in more than one language

    LanguageTool checks more than 30 languages, and its free plan covers 2,000 characters at a time. Premium costs $5.83 a month billed yearly. Grammarly added grammar and spelling checks in 17 more languages in March 2026, still in beta, and Paraphraser.io's free grammar checker lists 11 languages and accepts file uploads.

  • You are writing a book or a long report

    ProWritingAid adds line-editing reports and chapter feedback on top of grammar checks. It works in English only. Premium costs $10 a month billed yearly, and a lifetime plan is available.

Grammar checker or AI detector?

A grammar checker fixes your writing, while an AI detector estimates whether a text was written with AI. QuillBot includes a free AI detector, and Grammarly adds one on its Pro plan. For a dedicated detector, Pangram estimates how much of a document was written or edited with AI. It doesn't correct grammar, so we list it with our AI writing tools.

Guides and reviews

AI grammar checker FAQ

What is the best AI grammar checker in 2026?

QuillBot leads our 2026 rankings of AI grammar checkers at 4.3 out of 5, tied with Grammarly. It checks grammar, spelling and punctuation for free, and Premium costs $8.33 a month billed yearly. Grammarly is the better fit if you want checks and tone help across most apps. LanguageTool leads for other languages, and ProWritingAid for books and long reports.

Is there a free AI grammar checker?

Yes. QuillBot checks grammar, spelling and punctuation for free, and Grammarly's free plan fixes basic errors and adds 100 AI prompts a month. LanguageTool is free for 2,000 characters at a time, ProWritingAid for 500 words at a time, and Paraphraser.io's free grammar checker accepts .doc, .docx, .pdf and .txt files.

Is Grammarly better than QuillBot?

Grammarly and QuillBot share our 4.3 rating, and they suit different writers. Grammarly works in almost every app and its Pro plan adds tone changes and rewrites, at $12 a month billed yearly. QuillBot costs less, at $8.33 a month billed yearly, keeps grammar checks free and adds a paraphraser, summarizer and citation generator, useful for essays and coursework.

Which grammar checker works best in other languages?

LanguageTool is our pick for other languages. It checks more than 30, including German, French, Spanish, Dutch and Portuguese, and works in Word, Google Docs, Gmail and five browsers. Grammarly added grammar and spelling checks in 17 more languages in March 2026, in beta, but its tone and fluency help is still English-first.

Can a grammar checker tell if text was written with AI?

Some can. QuillBot includes a free AI detector, and Grammarly adds AI detection on its Pro plan. A grammar check itself doesn't judge who wrote a text. For a dedicated tool, Pangram estimates how much of a document was written or edited with AI. Treat any detector's result as a reason to look closer, not as proof.

Do I still need to proofread if I use a grammar checker?

Yes. Grammarly, QuillBot and the other tools here catch many spelling, grammar and punctuation errors, but they can miss context, names and facts, and some suggestions change your meaning. Accept changes one by one, and read the final text yourself before you send or publish it.

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About this page

What is listed
AI tools whose main job is checking grammar, spelling and punctuation. Most have a full review on this site. LanguageTool and ProWritingAid are listed because independent 2026 rankings consistently include them. Until we publish full reviews, their ratings are based on their vendors' pages and independent coverage.
Our picks
Best overall is always the highest-rated tool on this page. QuillBot and Grammarly share the top score; when two tools tie, the order between them is our editorial call. The strengths and limits listed for the picks come from our reviews and the vendors' own pages.
Ratings
Each rating is our overall score on a 5-point scale, and the list is ordered by it. A score rates the whole product, not only its grammar checking, so a tool with a paraphraser and citations is scored on all of it. The Best for line says who each tool suits.
Prices
The lowest paid plan on annual billing, read from each vendor's pricing or help pages on 18 October 2026. LanguageTool's prices change by location; we show the US rate. Paraphraser.io's Diamond plan is billed once a year, so its row shows the yearly price.
Update log
18 October 2026: new layout, picks explained in detail and every price rechecked. Trinka AI, Ginger, Scribbr and Wordtune taken off; LanguageTool and ProWritingAid now carry our 4.2 rating, and QuillBot our 4.3.