Grammar & Spelling Checker

Grammar & Spelling Checker reads your English as you write and underlines what looks wrong: misspelt words, “a” before a vowel sound, verbs that don’t agree with their subject, “should of” for “should have”, a doubled “the the”, a missing space after a comma and hundreds of other slips. Tap an underline to see what the problem is and pick a fix, or work down the list of issues beside the text.

Most online checkers send everything you type to a server. This one doesn’t. The checking is done by Harper, an open-source grammar engine from Automattic, running inside your browser. Emails, essays, cover letters and private notes stay on your device, and nothing is stored once you close the tab, apart from the words you choose to add to your own dictionary.

It is honest about what it is. Harper is rule-based, not AI: it follows thousands of written rules and a large dictionary, so it is fast and predictable, but it won’t rewrite a paragraph or judge your tone, and it will not catch every mistake. It checks English only, in American, British, Australian, Canadian or Indian spelling.

1. Type or paste into “Your text”, or press “Try an example” to see it at work.
2. Under “English”, choose American, British, Australian, Canadian or Indian English, so “colour” and “color” are judged the right way for you.
3. Tap or click any underlined word. A pop-up explains the problem and offers fixes; tap one to use it.
4. Or work through the “Issues” list. Use “Fix all” for a repeated slip, “Ignore” for a false alarm, and “Add to dictionary” for names and jargon.
5. Tap the Spelling, Grammar or Style counts to hide or show that kind of issue, then press “Copy text” when you are done.

• Live checking as you type, with the underlines kept in place while you edit.
• Three kinds of issue, each with its own line so colour is never the only clue: spelling (wavy line), grammar (double line) and style (dotted line).
• Click or tap an underline for a pop-up with the explanation and up to five suggestions; arrow keys open it too.
• “Fix all” applies the first suggestion to every identical slip at once, and Ctrl+Z or ⌘Z undoes fixes like any other edit.
• Your own dictionary for names, brands and jargon, saved in this browser, with a list where you can remove words again.
• Five spelling standards: American, British, Australian, Canadian and Indian English.
• Counts of spelling, grammar and style issues, plus words, characters, sentences and reading time.
• Runs in a background worker, so long documents don’t freeze the page, and nothing you type is sent anywhere.

• Pick your English first. In British English “colour” and “grey” are fine and “color” is flagged; in American English it is the other way round.
• Names of people, products and places are often flagged as spelling mistakes. Add them to your dictionary once and they stay quiet on later visits in this browser.
• Treat style notes as suggestions, not rules. A repeated word or a long sentence can be exactly what you meant.
• The first check downloads the checker, about 16 MB, which takes a few seconds on a slow connection. After that your browser keeps it, and checks take a fraction of a second.
• A clean result doesn’t mean perfect writing. Rule-based checks miss errors that depend on meaning, like “form” typed for “from”.