What it checks
- Spelling mistakes — checked against a common-typo dictionary of 150+ frequently misspelled words, plus wrong-word phrases like "could of" instead of "could have."
- Repeated words — catches accidental doubles like "the the."
- Long sentences — flags sentences over 30 words so you can consider splitting them.
- Punctuation spacing — spots stray spaces before punctuation and repeated punctuation marks.
- Passive voice — a heuristic check for "is/was/were + past participle" patterns worth a second look.
Live, in-text underlining
Turn Grammar check on in the left-hand toolbar and issues get underlined directly inside the text box as you type — red for spelling, orange for repeated words, purple for punctuation, and a dashed underline for possible passive voice. Turn it off any time without losing your work.
An honest note on accuracy
This is a lightweight, rule-based checker, not a full grammar engine. It's built to catch common, obvious issues fast during drafting — for a final, high-stakes document, it's still worth a careful human read-through.
Runs entirely in your browser
Nothing you type is uploaded anywhere. All checking happens locally with JavaScript, so your writing stays private. The grammar checker shares its editor with Toolioh's word counter, case converter, and character counter.