Grammar Checker
Paste your text and check for grammar, spelling, and punctuation errors. Uses Chrome's built-in Proofreader API with a rule-based fallback. Runs on your device — nothing is sent anywhere.
Multi-Tier AI: Chrome AI (fastest) → Transformers.js AI (works offline in any browser) → Rule-based analysis that checks 30+ common errors including misspellings, double words, and punctuation issues.
How the Grammar Checker Works
This tool checks your text for grammar, spelling, and punctuation errors using Chrome's built-in Proofreader API powered by Gemini Nano. When Chrome AI is unavailable, a comprehensive rule-based engine catches 30+ common writing mistakes including 70+ misspellings, repeated words, capitalization errors, and punctuation problems. Each issue is categorized as an error, warning, or style suggestion with a specific fix recommendation. Your text receives a score from A+ to F based on the number and severity of issues found.
What the Grammar Checker Catches
The checker covers four categories of writing issues. Spelling detection flags 70+ commonly misspelled words like "recieve," "definately," and "seperate" with correct alternatives. Grammar rules catch double words, missing articles before vowel sounds, and subject-verb mismatches. Punctuation checks identify missing periods, extra spaces, missing capitalization after sentence endings, and space-before-punctuation errors. Style analysis detects passive voice overuse and sentences exceeding 40 words, helping you write more directly and clearly.
Private Grammar Checking for Any Text
Your text is never sent to any server. Chrome runs the Proofreader API locally via Gemini Nano, and the rule-based fallback runs entirely in JavaScript within your browser. This makes the tool ideal for checking confidential documents, private messages, sensitive business writing, and academic work where privacy is essential. Unlike cloud-based grammar tools that store and analyze your writing on remote servers, every check happens on your device and disappears when you close the page.
How to Interpret Your Results
Review all sections of the analysis, not just the overall score. Focus on actionable items — findings you can actually change or improve. Run the check multiple times with different inputs if you want to compare scenarios. Keep in mind that automated analysis provides a useful starting point, but may not capture every nuance of your specific situation. Use the results as guidance for improvement rather than a definitive verdict.
Frequently Asked Questions
What kinds of errors does this tool catch?
The tool checks for spelling errors (70+ common misspellings), grammar issues (double words, article misuse), punctuation problems (missing periods, extra spaces, missing capitalization), and style suggestions (passive voice, long sentences).
Is my text kept private?
Yes. In AI mode, grammar checking runs entirely on your device via Chrome's Proofreader API. In fallback mode, all checks happen in JavaScript in your browser. Your text is never sent to any server.
How is the grammar score calculated?
The score starts at 100 and deducts points based on issues found: -10 per error, -5 per warning, -2 per style suggestion. Grades range from A+ (no issues) to F (many errors).
Is Grammar Checker free to use?
Yes, Grammar Checker is completely free with no sign-up, no login, and no hidden fees. The tool runs entirely in your browser — your data never leaves your device.
Is my data safe when using this tool?
Yes. This tool runs 100% in your browser using JavaScript. No data is sent to any server, stored in any database, or shared with any third party. When you close the page, processing stops immediately.