Grammar Checker

What this grammar checker actually catches

This tool runs your text through a set of pattern-based checks for the mistakes that show up most often in everyday writing: commonly confused word pairs (their/there, your/you're, would of/would have), doubled words, missing spaces after punctuation, repeated punctuation marks, sentences that don't start with a capital letter, and sentences that have grown long enough to hurt readability. Everything runs in your browser - nothing you type is sent anywhere.

Why it's scoped to pattern-matching, not full grammar parsing

It's intentionally built around mechanical, pattern-matchable issues rather than full sentence-level grammar analysis - subject-verb agreement across complex clauses, tense consistency across a whole passage, or deeper style judgment all require genuine linguistic parsing that a pattern-matching tool like this one doesn't attempt. For that level of checking, you still need either a careful human read-through or a full NLP-based grammar engine.

The specific checks it runs

Beyond the confused-word patterns, it flags doubled words ("the the"), double spaces, repeated punctuation marks like multiple exclamation points, a missing space right after a comma or period, sentences that start with a lowercase letter, sentences running past roughly 40 words, and passive-voice constructions (a "to be" verb followed by a past participle, like "was written" or "is made"). The long-sentence and passive-voice flags are both style suggestions rather than hard grammar rules - neither is technically wrong, they're just worth a second look.

A genuinely private first pass

Because every check runs as JavaScript directly in your browser, nothing you paste in is ever transmitted to a server - useful when checking drafts you aren't ready to share, or simply when you want an instant result with zero wait and zero account required.

よくある質問

Does this catch every grammar mistake?

No - it is built to flag common, pattern-matchable mistakes (confused words, typos, spacing, repeated words, overlong sentences) rather than perform full linguistic parsing. It is a useful first pass, not a substitute for proofreading.

Is my text uploaded anywhere?

No - the check runs entirely in your browser with JavaScript. Nothing you type is sent to a server.

Why did it flag a sentence that looks fine to me?

Some checks (like the long-sentence warning) are style suggestions rather than hard rules. A 45-word sentence is not wrong - it is just worth a second look for readability.

Can this catch subject-verb agreement errors like "they was"?

Not reliably for complex sentences - this checker is pattern-based rather than a full grammar parser, so it focuses on common confused-word pairs, typos, and spacing rather than deep grammatical analysis across varied sentence structures.

Why does it flag "would of" but not every incorrect word usage?

The checker's confused-word list covers specific, well-known mistakes that are almost always errors rather than style choices (like "would of" for "would have") - it's deliberately limited to patterns that are reliable enough not to produce excessive false flags.

Is passive voice actually a mistake?

No - passive voice is grammatically correct and sometimes the better choice (for example, when the actor is unknown or unimportant). It's flagged only as a style suggestion, since active voice is often more direct, not because passive voice is wrong.

Does this tool have a tone detector or writing-style score like some other grammar checkers?

No - genuine tone detection needs real natural-language-processing models, not pattern matching, so adding one here without that would mean either a fake result or an expensive API behind a "free" tool. This checker stays honest about what pattern-matching can and can't do.