How to Convert Hiragana and Katakana to Romaji

Native Writing System

Japanese uses two phonetic syllabaries—hiragana (ひらがな) for native lexical items and grammatical particles, and katakana (カタカナ) for foreign loanwords, onomatopoeia, and emphasis. Both consist of 46 basic symbols that represent morae, not individual phonemes. Kana are used alongside kanji (logographic characters) and a limited set of punctuation marks.

Major Romanization Systems

All three systems are ISO‑compatible, but the Japanese Ministry of Education endorses Hepburn for most public‑facing material.

Recommended System by Use Case

• Academic papers & linguistic research: Traditional Hepburn with macrons (e.g., ō, ū) because it preserves vowel length and matches IPA conventions.
• Travel, tourism & everyday communication: Modified Hepburn without macrons (e.g., ou for long o) for ease of typing on standard keyboards.
• Digital databases & software development: Kunrei‑shiki or JSL, as they are algorithmically reversible and avoid special characters.

Alphabet or Character Chart

Vowels

Japanese has five pure vowel qualities. In Hepburn, long vowels are marked with a macron (ā, ī, ū, ē, ō) or, in informal contexts, with a doubled vowel sequence (aa, ii, uu, ee, oo).

• a – /a/ as in “father”.
• i – /i/ as in “machine”.
• u – /ɯ/ a close back unrounded vowel, similar to the “oo” in “food” but without lip rounding.
• e – /e/ as in “bed”.
• o – /o/ as in “go”.

Long vowels double the mora count and can change meaning, e.g., obasan “aunt” vs. obaasan “grandmother”.

Consonants

Consonants in Japanese always attach to a vowel, forming a mora. The most common consonant‑vowel combinations are shown below.

• k – ka, ki, ku, ke, ko
• s – sa, shi, su, se, so (note “shi” for し)
• t – ta, chi, tsu, te, to (note “chi” and “tsu”)
• n – na, ni, nu, ne, no
• h – ha, hi, fu, he, ho (note “fu” for ふ)
• m – ma, mi, mu, me, mo
• y – ya, yu, yo (no native “yi” or “ye”)
• r – ra, ri, ru, re, ro (flapped alveolar approximant)
• w – wa, (wo) – historically “wo” is now pronounced “o”.

Diacritics and Tone Marks

Word Separation

Japanese script does not use spaces. In Romaji, spaces are inserted to reflect lexical boundaries, improving readability for non‑native readers. The standard practice is:

1. Separate content words (nouns, verbs, adjectives).
2. Attach particles directly to the preceding word (e.g., watashi wa).
3. Retain hyphens only for compound foreign loanwords where the original spelling includes them.

Capitalization

Romaji follows English capitalization rules:

• Sentence‑initial word: first letter capitalized.
• Proper nouns (personal names, place names, brand names): each component capitalized (e.g., Tokyo Tower).
• Acronyms derived from Japanese (e.g., JAL for Japan Airlines) retain uppercase.

Names

Japanese personal names are traditionally written family name first. In most English contexts the order is reversed, but official documents may keep the Japanese order. When romanizing:

• Use Hepburn with macrons for academic citations (e.g., Mishima Yukio).
• For passports and travel, follow the UNGEGN recommendation: family name in all caps, given name in normal case (e.g., MISHIMA Yukio).

Place Names

Geographic names are standardized by the Japanese Geospatial Information Authority (GSI) using Hepburn. Examples include:

• 京都 → Kyoto
• 大阪 → Osaka
• 長野県 → Nagano‑ken (the suffix “‑ken” denotes a prefecture).

When a place name contains a long vowel, the macron is retained in formal writing but often omitted in travel literature (e.g., Tōkyō vs. Tokyo).

Examples

Three real‑world sentences are presented in native kana, Hepburn romanization, and a brief pronunciation guide.

“今日はいい天気です。” – Kyou wa ii tenki desu. – /kʲoː wa iː teŋki desɯ/ – “The weather is nice today.”

“寿司が好きです。” – Sushi ga suki desu. – /sɯɕi ŋa sɯ̥ki desɯ/ – “I like sushi.”

“東京タワーは高いです。” – Tōkyō Tawā wa takai desu. – /toːkʲoː tawaː wa takai desɯ/ – “Tokyo Tower is tall.”

Alternative Spellings

Older textbooks sometimes use Kunrei‑shiki or Nihon‑shiki spellings, which replace “shi” with “si”, “chi” with “ti”, and “tsu” with “tu”. While reversible, they can be confusing for English speakers because they do not reflect actual pronunciation.

Example: しょくじ → shokuji (Hepburn) vs. syokuzi (Kunrei‑shiki).

Pronunciation Limitations

Romaji cannot capture every phonetic nuance of Japanese:

• The moraic n (ん) varies before labial, alveolar, and velar consonants; Romaji always shows a simple “n”.
• Pitch‑accent is invisible in Hepburn; learners must rely on audio or IPA.
• Long vowels sometimes rendered as double letters may mislead readers about spelling versus pronunciation.

Work‑arounds include appending IPA brackets after the Romaji or using macrons consistently for academic work.

Converter

Several reliable online tools automate kana‑to‑Romaji conversion:

• Hepburn Converter – Supports macrons, sokuon, and handakuten.
• Kunrei‑shiki Converter – Ideal for reversible database entries.
• JSL Converter – One‑to‑one mapping without diacritics.

These tools allow batch processing, custom mappings, and preview of IPA output.

“Consistent romanization is essential for scholarly communication; otherwise, the same Japanese term can appear in dozens of orthographic variants.” – Dr. Haruko Tanaka, Professor of Japanese Linguistics, University of Tokyo.