Japanese On/Kun Reading Annotator

Annotate kanji in text with both on'yomi and kun'yomi readings

Shows on'yomi (Chinese-derived) and kun'yomi (native Japanese) readings for each kanji in pasted text using a built-in table of common JLPT kanji, with romaji and kana. It runs free in your browser on Gera Tools, with nothing uploaded.

Last updated Source: Gera Tools

What is the difference between on'yomi and kun'yomi?

On'yomi is the reading borrowed from Chinese when the kanji was imported, usually written in katakana in dictionaries. Kun'yomi is the native Japanese reading assigned to the same character's meaning, written in hiragana. Many kanji have both.

This tool annotates Japanese text with both on’yomi (音読み, the Chinese-derived reading) and kun’yomi (訓読み, the native Japanese reading) for each kanji it recognises, using a built-in table of common JLPT characters. Many kanji carry both reading types, and knowing which applies is one of the hardest parts of learning Japanese — this gives you both at a glance, with a short meaning hint.

How it works

The tool walks your text and, for each kanji in the bundled table, shows:

  • On’yomi in katakana — the reading used mostly in compound words.
  • Kun’yomi in hiragana — the reading used when the kanji stands alone or has okurigana.
  • A short English gloss to help confirm the character.

Kana, Latin letters, and punctuation are skipped. A handy rule of thumb: on’yomi tends to surface inside jukugo (multi-kanji compounds) such as 学校 → gakkō, while kun’yomi appears when the kanji is solo or paired with hiragana endings, such as 学ぶ → manabu.

Why kanji have multiple readings

Kanji were introduced to Japan from China in multiple waves over many centuries, each time bringing the Chinese pronunciation current at that period. This is why a single kanji can carry two or more on’yomi from different eras or dialects of Middle Chinese. The native Japanese reading (kun’yomi) was then attached to the same character to represent the existing Japanese word with that meaning.

A practical example: 生 carries on’yomi セイ (from one period of borrowing) and ショウ (from another), plus kun’yomi い・きる (to live), う・まれる (to be born), なま (raw), き (pure), and more. Seeing them all listed together makes it clear why context is essential for choosing the right reading.

When on’yomi versus kun’yomi applies

The compound word rule is a useful heuristic but has important exceptions:

  • Most two-kanji compound nouns (jukugo) use on’yomi throughout: 学校 (gakkō), 音楽 (ongaku), 電話 (denwa).
  • A kanji standing alone as a verb or adjective root typically uses kun’yomi: 食べる (た・べる), 白い (しろ・い).
  • Mixed readings — called 重箱読み (jūbako-yomi) and 湯桶読み (yutō-yomi) — occur in common words where one kanji uses on and the other uses kun: 本棚 (hon-dana, on+kun) and 場所 (ba-sho, kun+on).
  • Name readings (名乗り, nanori) are a separate category not covered by this tool; given names often use unusual or unique readings that do not appear in standard dictionaries.

Example and notes

Paste and you will see both kun’yomi (い・きる, う・まれる, なま) and on’yomi (セイ, ショウ) — a famously many-reading kanji. Because the table only reports stored readings, rarer kanji and name readings may show as “not found”; that is deliberate so you never get a fabricated reading. Use the meaning hint to disambiguate which reading fits the word you are reading. Nothing you paste is uploaded.