Japanese Kana Converter (Hiragana, Katakana, Romaji)
Convert between hiragana and katakana (half-width too), turn kana into romaji with modified Hepburn, the 2025 Japanese Cabinet rules or passport style, and romaji back into kana. Long vowels and particles are flagged.
- Runs in your browser with cited reference data
Long vowels as ā, ū, ē, ō (いい and えい stay ii and ei). ん is n, written n' before a vowel or y. っち is tch.
Kanji are not converted because their reading cannot be known. Type the text in kana; add spaces to separate words.
Result
Please check
- おう, おお, うう, ああ and ええ were joined into long vowels (ō, ū, ā, ē). Fix them by hand where they are not long vowels: across word parts (子牛 こうし → koushi), at verb endings (思う おもう → omou) or in names such as 井上 いのうえ → Inoue. Examples: とう → tō / きょう → kyō
- は and へ were written ha and he. When they are particles they are written wa and e (this cannot be detected automatically). Examples: し は
Conversion rules with examples
Examples converted with “Modified Hepburn (Library of Congress ALA-LC table)”.
| Rule | Example | Result |
|---|---|---|
| Contracted sounds (きゃ, きょ…) | きょうと | kyōto |
| Small っ (double consonant) | がっこう | gakkō |
| っ before ち (っち) | まっちゃ | matcha |
| Syllabic ん | しんぶん | shinbun |
| ん before a vowel | きんえん | kin'en |
| Long vowel おう | とうほく | tōhoku |
| Long vowel おお | おおさか | ōsaka |
| Long-vowel mark ー | ラーメン | rāmen |
| いい and えい | にいがた せんせい | niigata sensei |
| Particle は | わたしは | watashiha |
How to use
- Choose the conversion: hiragana → katakana, katakana → hiragana, kana → romaji or romaji → kana.
- For romaji pick the system, for katakana choose whether to output half-width, then type or paste the text.
- Copy the result. Check the places listed under “Please check” (long vowels, particles, ぢ / づ…) and fix them by hand where needed.
FAQ
Why does おもう become omō?
From kana alone it is impossible to tell whether う lengthens the vowel or belongs to the next part of the word, so おう, おお and similar pairs are always treated as long vowels and listed for you to check. Verb endings such as 思う (omou) need to be fixed by hand. The “doubled vowels” system of the 2025 Cabinet Notice writes them exactly as in kana (tou, omou).
How do the systems differ?
Modified Hepburn and the 2025 Cabinet Notice both write ん as n (n' before a vowel or y), but write っち as tch and cch respectively. Passport style is upper case, leaves out long O and U, and writes ン before B, M and P as M.
Can it convert kanji?
No. The reading of kanji cannot be decided without a dictionary, so they are kept as they are and listed. Type the text in kana.
Notes & limitations
- What you enter is processed only on this page and is not sent to YUCTS servers.
- Word boundaries, particles (は, へ, を) and whether a vowel is long cannot be known without context, so the rules are applied mechanically. Always check the result.
- Passport names follow the Ministry of Foreign Affairs table, but the final spelling can differ depending on the passport office or the holder’s wishes (such as OH for long O).
- Loanword sounds such as ティ and ファ follow the ALA-LC table; the 2025 Cabinet Notice does not cover them.
Data sources
- Library of Congress — Japanese Romanization Table (ALA-LC)(opens in a new tab) (2022) — Checked on: 2026-11-06
- 文化庁「ローマ字のつづり方」（令和7年内閣告示第4号）(opens in a new tab) (2025) — Checked on: 2026-11-06
- 文化庁「ローマ字のつづり方」（令和7年内閣告示第4号）に関するQ&A(opens in a new tab) (2026-02) — Checked on: 2026-11-06
- 外務省 パスポート「ヘボン式ローマ字綴方表」(opens in a new tab) — Checked on: 2026-11-06
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