Japanese Grammar Checker
Fix your Japanese instantly. AI-powered corrections with explanations for grammar,
tone, and natural phrasing.
What the Japanese grammar checker looks at
Most grammar checkers were built for English and treat Japanese as an afterthought,
which is why they catch a missing 。 and miss everything that actually makes writing
read as foreign. Fix My Japanese checks the things that go wrong in Japanese
specifically:
-
Particles:
は against が, に against で, を against が with potential verbs. This is the single
biggest source of corrections, and the one where knowing why
matters more than the fix.
-
Conjugation and tense:
て-form, conditionals, transitive against intransitive pairs
(開ける / 開く), and the tense shifts that Japanese handles differently from English.
-
Politeness and keigo:
whether the text holds one register the whole way through, and whether that
register fits what you are writing. A 敬語 email that drops into plain form in the
third paragraph is a mistake no spell checker will ever flag.
-
Natural phrasing:
sentences that parse correctly but no native speaker would write, usually because
they were assembled from English word order or a dictionary's first entry.
-
Kanji, okurigana and typos:
the wrong homophone picked during IME conversion, okurigana that is too long or
too short, and katakana spellings that are near-misses.
Every correction comes with the reason
A corrected sentence on its own teaches you nothing. You will make the same mistake
next week. Each change is listed separately with the original text, the replacement,
and a short explanation of the rule or the usage behind it. You can read the
corrections one at a time and skip the ones you already understand.
You also choose the tone the text should end up in: casual for messages to friends,
polite for everyday writing, formal or keigo for work. The checker corrects toward
the register you picked instead of flattening everything into textbook 丁寧語, so the
same paragraph can be checked as a LINE message or as a client email and get
different, equally correct answers.
It is built for anyone writing Japanese that other people will read: learners working
through JLPT grammar, exchange students, people who moved to Japan for work and now
write business email in their second language, and translators who want a second pair
of eyes before sending. Nothing you paste is required to be short, and nothing needs
an account.
Worked corrections
Three real examples of the kind of thing the checker catches and how it explains
itself.
Particles
✗
私は公園で行きました。
✓
私は公園に行きました。
行く takes に for the destination. で marks the place an action happens in: 公園で遊びました is fine, 公園で行きました is not.
Natural phrasing
✗
私の趣味は本を読むことが好きです。
✓
私の趣味は本を読むことです。
「趣味は〜です」 and 「〜が好きです」 are two separate patterns. Combining them gives the sentence two predicates, which is grammatical-looking but not something a native speaker writes.
Keigo
✗
明日の会議に参加できません。すみません。
✓
明日の会議に参加できず、申し訳ございません。
すみません is fine spoken, but too light for a written apology to a client or manager. 申し訳ございません is the expected register, and 〜できず connects the two clauses the way business Japanese does.
Frequently asked questions
- Is this correct in Japanese?
- Paste the sentence into the box above and hit Fix It. If it is already natural, the checker says so and leaves it alone. If it is not, you get the corrected sentence plus an explanation of what was off, which is usually the part you actually wanted to know.
- How do I check my Japanese grammar?
- Paste any Japanese text (a sentence, a LINE message, a whole email) into the box and submit it. There is no sign-up and no install. The checker reads the whole passage rather than one sentence at a time, so it catches mistakes that only show up in context, such as a politeness level that shifts halfway through.
- What is a bunpou check?
- 文法 (bunpou) is the Japanese word for grammar, so a bunpou check and a Japanese grammar check are the same thing. What makes it nihongo-specific is what gets looked at: particles, conjugation, keigo, and phrasing that is technically correct but reads as translated. A checker built for English will not examine any of those, which is why running Japanese through one tends to come back clean.
- Does it do Japanese spell check as well as grammar?
- Yes. Alongside grammar it catches the mistakes that are specific to writing Japanese: wrong kanji picked during IME conversion (返る for 帰る), okurigana that is too long or too short (行なう for 行う), and katakana spellings that are close but not standard.
- Can it check keigo and business Japanese?
- Yes, and it is one of the more useful things to run through it. Pick the tone you are aiming for (casual, polite, formal or keigo) and the checker flags anything that does not match, including the very common case of a 敬語 email that slips into plain 丁寧語 in the middle.
- Is this an AI Japanese checker?
- Yes. The corrections come from a language model rather than a fixed list of rules, which is what lets it weigh tone and natural phrasing instead of only conjugation and particles. It also means every change arrives with a reason you can read and push back on, because a model can misread your intent in a way a rule never does.
- Is Fix My Japanese free?
- The checker is free to use without an account. Signing in saves your correction history, and Pro unlocks the slower, more thorough correction modes and longer texts.
- What level of Japanese is it for?
- Anything from a first N5 sentence to native-level business writing. Beginners tend to use it for particles and conjugation; advanced learners and people working in Japanese use it mostly for tone and natural phrasing, where the text is already grammatical but reads as translated.
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