Online Tool Store
Grammar Checker
Check grammar, spelling and style with plain-English explanations, a readability score, and long-sentence flags. Copy the report as text.
This works right here on your device — nothing gets sent out.
How it works
- Paste or type your text into the box.
- Checks run automatically as you type (briefly debounced so it doesn't lag on long text).
- Each issue found shows the flagged snippet, a plain-English explanation, and which category it falls under.
- Check the readability estimate above the results, and use "Copy report" to export every issue as text.
What it actually checks
Four independent passes over the text, each looking for a different, narrow class of issue — no AI model, no server, nothing sent anywhere:
- Grammar — "could of" → "could have", missing capital letters after a sentence ends, and a/an agreement (with common exceptions like "an hour" and "a university").
- Spelling — a curated list of frequently misspelled words (definately, seperate, recieve, and similar), plus "alot" → "a lot".
- Style — likely passive voice, vague "weasel words" (very, basically, several…), wordy phrases ("due to the fact that" → "because"), repeated words, sentences over 35 words, and sentences that open with "So" or "There is/are".
- Worth checking — every occurrence of commonly confused words (its/it's, your/you're, their/there/they're, affect/effect) is flagged as a reminder, whether or not it's actually wrong, since telling them apart correctly needs to understand the sentence's meaning.
A readability estimate (Flesch Reading Ease, 0-100) sits above the results, using the standard formula with an approximate, dictionary-free syllable count — useful for comparing drafts, not a precise measurement.
This is rule-based pattern matching, not language understanding — it won't catch every grammar mistake (subject-verb agreement across a complex sentence, wrong verb tense, and similar issues are out of reach for this approach), and it can occasionally flag something that's actually fine. Treat it as a first pass, not a final proofread.
FAQ
Is this as thorough as Grammarly or Microsoft Editor?
No, and it doesn't try to be. Those tools run large language models on a server, which means your text has to leave your device. This one runs a fixed set of rules — common mix-ups, misspellings, and prose-style checks like passive voice — entirely in your browser, so it's more limited but keeps everything local.
Why does it flag words like "its" or "your" even when I used them correctly?
Those are listed under "Worth checking," not "Grammar" — a deliberate, lower-confidence category. Telling "its" from "it's" correctly requires understanding the sentence's meaning, which simple pattern matching can't do reliably, so every occurrence is flagged as a reminder to double-check rather than a claimed error.
Does it check spelling for every word, like a dictionary?
No — it checks against a curated list of commonly misspelled words (definately, seperate, recieve, and similar), not a full dictionary. It won't catch every typo, and it won't flag words it doesn't recognize as simply unusual.
What's a false positive I should expect?
The a/an check assumes standard pronunciation, so unusual cases can trip it up, and the missing-capital check can misfire after abbreviations like "Dr." or "U.S." — both are noted limitations, not bugs to report.
What is the readability score?
An estimated Flesch Reading Ease score from 0-100, using the standard published formula. The word-per-sentence part is exact; the syllables-per-word part uses a vowel-group heuristic rather than a dictionary, so treat the score as an estimate, not an exact measurement — it is still useful for comparing drafts.
Does it flag long or run-on sentences?
Yes — a sentence over 35 words is flagged as worth splitting for easier reading. This counts words only; it does not judge whether the sentence is actually a grammatical run-on.
Can I export the results?
Yes — "Copy report" copies every flagged issue as a numbered, plain-text list, ready to paste into a document, ticket, or email.
Is my text uploaded or stored anywhere?
No. Every check runs in your browser using JavaScript — nothing you type is sent to a server, saved, or logged.
How we compare
| Feature | Online Tool Store | GrammarCheck.net | GPTZero | NoteGPT |
|---|---|---|---|---|
| Runs entirely in the browser — nothing sent to a server | ✓ | ✗ | ✗ | ✗ |
| No sign-up | ✓ | Not required | Not required | Not required |
| No word/character limit | ✓ | 10,000-character limit | 10,000-character limit | 20,000-word limit |
| Readability score shown | Yes, estimated | Readability level assessment | Not listed | Not listed |
| Copy results as a report | ✓ | Not listed | Not listed | Copy or download as DOC/PDF |
| Deep, context-aware grammar correction | No | ✓ | ✓ | ✓ |
GrammarCheck.net, GPTZero and NoteGPT can correct far more than this tool, since they run a full language model on a server. If keeping a draft off a third-party server matters more than deep AI-level correction — internal notes, something not ready to share — this catches the common slips, estimates readability, and lets you export the findings, without your text leaving your device. For a genuinely thorough pass, a server-backed tool will catch more.