AI Grammar Checker
Correct grammar, spelling and punctuation — and see exactly what was changed.
Before you use this: These AI tools run on a free Cloudflare allowance, so they are limited to 5 requests per person per day. Every other tool on this site is unlimited — the difference is that those run entirely on your device, while this one needs a server.
Result
How to use this tool
- Select your file, drag it onto the box above.
- Processing starts automatically — there is nothing to configure.
- Check the result panel, which shows the original size, the final size and the page count.
- Click Download to save it.
It returns the corrected text followed by a list of the changes, so you can see what it did rather than trusting it blindly. It is instructed to fix what is wrong rather than rewrite for style.
The specification
| Input | Up to 6,000 characters |
|---|---|
| Output | Corrected text, then a list of changes |
| Scope | Grammar, spelling, punctuation |
| Limit | 5 per day per person |
| Not included | Style rewriting — use the rewriter for that |
How it works
This is the one part of the site that needs a server. A language model cannot run in a browser at usable speed, so your text is sent to a small Cloudflare Worker, processed at the edge, and returned. The file — where there is one — never leaves your device; only text does.
How it is kept safe and free: there is no API key anywhere, because Cloudflare's AI is bound directly to the Worker rather than authenticated with a token that could be stolen from the page. The prompts live on the server, not in your browser, so the endpoint cannot be repurposed as somebody's free chatbot. An invisible human check and a per-person daily cap keep the shared free allowance available to actual visitors.
Nothing you send is stored, logged, or used for training.
Who uses this
Checking an important email, a cover letter, or anything written in a second language before sending it.
Other names for this tool
People look for this under several different names. If you arrived searching for any of the following, this is the right page — they all describe the same thing:
- ai grammar checker online
- free ai grammar checker
- ai grammar checker tool
- online ai grammar checker free
Frequently asked questions
Is it as good as a human proofreader?
No. It catches most grammar and spelling errors reliably, but it can miss context-dependent mistakes and occasionally "corrects" something that was right. Review the change list rather than accepting everything.
Does it work for non-native English?
Yes, and that is where it helps most — article usage, prepositions and tense agreement are the errors it catches most consistently.
Is my text sent to a server?
Yes — and this is the one part of the site where that is true. AI needs a model that cannot run in a browser, so your text goes to a Cloudflare Worker, is processed, and comes straight back. It is not stored, not logged, and not used for training. If that matters for your document, use the tools that run fully on your device instead.
Why only 5 uses a day?
The AI runs on Cloudflare's free tier, which gives the whole site a fixed daily allowance. Without a per-person cap, one script could drain it before breakfast and nobody else would get to use it. The limit resets at midnight UTC.
Can I trust the output?
Read it before you use it. Language models produce fluent text that can still be wrong, and they occasionally invent detail. The prompts here explicitly instruct the model not to add facts you did not provide, but treat every result as a first draft to check, not a finished document.
Is this tool really free?
Yes — no account, no trial, no watermark, and no cap on usage. It runs on your own device rather than our servers, so there is no cost for us to pass on.
Does it work on mobile?
Yes. The interface adapts to phone and tablet screens, and everything runs in the browser, so there is no app to install.
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Your files stay on your device. This tool runs entirely in your browser. No file is uploaded, transmitted, or stored. You can verify this by opening your browser's Network tab while using the tool.
Disclaimer. Specifications published by exam boards, governments and platforms change without notice. We verify and date every specification on this site, but you should always confirm against the official source before submitting an application. See our full disclaimer.