How to use the grammar checker
- Type or paste your text, or press Try an example, and choose your English (US, UK, Australia, Canada or India).
- Press Check grammar. Mistakes are underlined: red for spelling, amber for grammar, blue for punctuation and purple for style.
- Tap an underlined word, or use the list below the text, and pick a suggestion. Ignore hides one you disagree with.
- Accept all applies the first suggestion everywhere; Undo takes it back. Then copy the text or download it as a .txt file.
After the first check it keeps checking as you type, with up to 30,000 characters (about 5,000 words) at a time.
How it works
The checker is Harper 2.10.0, an open-source grammar engine by Automattic under the Apache-2.0 licence. It runs in your browser as WebAssembly, in a background thread, so typing stays smooth and nothing is sent to a server. Harper uses hundreds of hand-written rules and a dictionary rather than an AI model, so it gives the same answer every time and needs no connection once loaded, but it only knows English and only the mistakes its rules describe.
Example
The example text has 12 mistakes the checker finds, including “Their is”, “She have went”, “buyed a apple”, “recieve alot”, “could of” and “the the”. Accept all turns it into “There is no reason to worry. She has gone to the store twice this week and bought an apple. I receive a lot of emails every day, which is really annoying. We could have left earlier, but the bus was late.”, and a second check finds nothing.
Tips
- Check suggestions before accepting them: a rule can pick the wrong word, for example for a name it doesn't know.
- Add your own names and terms to the dictionary once, so they stop being flagged.
- For text in a photo, screenshot or scan, get it out with Image to Text first, then paste it here. To count words only, use the word counter.