Hangul Romanizer
Romanise Korean with the official Revised Romanization, including the sound-change rules.
The official South Korean standard, which romanises how the word is pronounced rather than letter by letter.
Personal names follow their own conventions — many Koreans spell their name a fixed way that predates the standard, and that spelling is the one to use. Place names on official signage follow the standard as shown here.
Revised Romanization writes Korean as it is pronounced, not letter by letter. 한국어 becomes hangugeo rather than hankukeo, because the ㄱ closing 국 moves into the empty ㅇ that opens 어, and 신라 becomes Silla rather than Sinla.
Hangul is built, not listed
Every Korean syllable block is assembled from an initial consonant, a vowel, and an optional final consonant. That structure is encoded directly in Unicode, so a romanizer does not need a lookup table of syllables — it can take any of the 11,172 possible blocks apart arithmetically and rebuild it in Latin letters.
The same consonant is romanised differently depending on where it sits. ㄱ is g at the start of a syllable but k at the end, which is why 김 is gim and 국 is guk. That positional difference is the first thing that separates a correct romanizer from a naive letter swap.
Pronunciation, not spelling
Revised Romanization is the official South Korean standard, adopted in 2000, and its central choice is to follow sound. Korean consonants change when they meet across a syllable boundary, and the romanisation shows those changes. 종로 is written with ㅇ and ㄹ but pronounced — and romanised — Jongno. 신라 becomes Silla. 입니다 becomes imnida.
This is why the output can look surprising next to the letters on the page, and why the converter lists which rules fired on your text. It is also why a character-by-character transliteration, which some tools produce, disagrees with signage and official documents.
Worked example: 한국어
Take the blocks apart, then let the boundary rules act:
- 1 Split each block into jamo. 한 is ㅎ + ㅏ + ㄴ, 국 is ㄱ + ㅜ + ㄱ, and 어 is ㅇ + ㅓ.
- 2 Romanise by position. Initial ㄱ is g and final ㄱ is k, so in isolation the blocks read han, guk, and eo.
- 3 Look at the boundary. 어 opens with ㅇ, which carries no sound. The final ㄱ of 국 moves across to fill it.
- 4 Apply the liaison. Now in initial position, that ㄱ is romanised g, so 국어 reads gugeo rather than guk-eo.
- 5 Join the syllables. han + gu + geo gives hangugeo.
Sound-change rules this converter applies
Revised Romanization reflects pronunciation, so these changes are part of the standard rather than optional refinements.
| Rule | What happens | Example |
|---|---|---|
| Liaison | A final consonant moves into a following silent ㅇ | 한국어 → hangugeo |
| Nasalisation | k, t, p before ㄴ or ㅁ become ng, n, m | 입니다 → imnida |
| Liquid assimilation | ㄴ next to ㄹ becomes ll | 신라 → Silla |
| ㄹ after a nasal | ㄹ becomes n, nasalising what precedes | 종로 → Jongno |
| Aspiration | ㅎ merges with a neighbouring plain stop | 좋고 → joko |
| Palatalisation | ㄷ and ㅌ before 이 become j and ch | 같이 → gachi |
Names are the exception
The standard applies to place names, signage, and general text. Personal names do not follow it in practice. Many Koreans spell their name in a way settled long before 2000 — Lee rather than I, Park rather than Bak, Kim rather than Gim — and that spelling is the one to use on documents, papers, and correspondence. The standard itself allows for this.
You may also meet McCune-Reischauer, the older system still used in North Korea and in much academic writing. It uses breves and apostrophes — Pusan, ch’ŏn — where Revised Romanization uses plain letters, giving Busan and cheon. Neither is wrong; they answer to different authorities.
Two limits worth stating plainly. A handful of sound changes depend on the specific word rather than the letters — 밟다 is one, where the usual reading of ㄼ does not apply — and no rule-based converter can catch those. And where a syllable boundary falls inside a compound word, official practice sometimes keeps the original letters rather than showing the change, which is why a few place names on signage differ from what the rules alone would produce.