100% Free  ·  No Signup  ·  No Upload

AI Grammar Checker — Fix Grammar & Style Free

Fix grammar while keeping your writing style. Works entirely in your browser. Your files never leave your device.

Open AI Grammar Fixer Free
No file uploadNo account needed100% privateWorks offlineAlways free
⚙️Checking grammar...

What is AI Grammar Fixer?

AI Grammar Fixer is a free tool powered by Claude AI that corrects grammar errors, spelling mistakes, punctuation issues and awkward phrasing in any text. Paste your writing and the AI rewrites it with correct grammar while preserving your original meaning, tone and style as closely as possible.

Unlike basic spell checkers that flag individual words, the AI understands sentence structure and context. It can identify subject-verb disagreement, incorrect tense shifts, dangling modifiers, comma splices, and style issues like overly passive constructions or redundant phrases. The corrections are applied intelligently rather than mechanically.

Common use cases include proofreading professional emails before sending, improving non-native English writing, cleaning up rough drafts of articles or reports, fixing grammar in student essays, and preparing social media content for publication. The tool is particularly useful for writers who are confident in their ideas but less confident in grammar rules.

⚡
Instant results
No server processing or wait
🔒
100% private
Files stay on your device
💰
Always free
No subscription or fees
📱
Mobile ready
Works on any device

How to use AI Grammar Fixer

  1. Paste or type the text you want grammar-checked
  2. Click Fix Grammar — Claude AI scans for errors, awkward phrasing and typos
  3. Review the corrected text with improvements highlighted
  4. Copy the polished text ready to use

Why use OnlineToolsPlus?

AI tools on OnlineToolsPlus use the Claude API — one of the most capable AI models available. You bring your own API key, which means your text goes directly to Anthropic's servers (not through OnlineToolsPlus), and you pay only for what you use. This gives you full control over cost and privacy while accessing professional-grade AI writing assistance.

Frequently asked questions

Does grammar fixing change my writing style?
The tool corrects errors while trying to preserve your voice. Unusual but intentional stylistic choices may occasionally be flagged. Review suggestions before accepting them.
Does this work for non-native English speakers?
Yes. It handles common patterns from non-native speakers well, including characteristic errors from speakers of specific language backgrounds.
Can it fix grammatical errors in academic writing?
Yes. Academic writing, business writing, and casual writing are all handled. For academic submissions, review the output yourself as a final check.
Does this need an API key?
Yes. A free Anthropic API key is required from console.anthropic.com.
How is this different from spell check?
Spell check only catches misspelled words. Grammar checking catches wrong words that are spelled correctly (there/their), sentence structure errors, tense inconsistency, subject-verb disagreement, and awkward phrasing.
Is there a word limit?
Best results for texts under 2000 words. Longer texts can be processed in sections.

More AI Tools

AI HumanizerMake AI-generated text sound human & naturalAI DetectorDetect if text was written by AI or humanAI SummarizerSummarize any text or article instantlyAI ParaphraserRewrite text keep meaning, change wordingAI Email WriterWrite cold emails, follow-ups, complaints

Last updated: April 11, 2026

View all 200+ free tools →