RTGS is the Royal Thai General System of Transcription, the official Thai government standard for writing Thai in the Latin alphabet. It is the spelling seen on Thai street signs and maps, and it deliberately omits tone and vowel-length marks.

Why do some consonants romanize differently at the end of a word?

Thai consonants change their pronounced value in final position. For example ส, ช, and จ all sound like a t at the end of a syllable, so RTGS writes them as t there even though they begin with s, ch, and ch sounds initially.

Does RTGS show tones?

No. RTGS is a transcription, not a transliteration, and intentionally drops the four Thai tones and the distinction between long and short vowels. Two different Thai words can therefore share the same RTGS spelling.

Why does my result differ from a Thai name I have seen?

Many Thai personal and brand names use older or personal romanization schemes (such as Bhumibol or Suvarnabhumi) that predate or ignore RTGS. RTGS is one consistent system, but it is not the only one in use, so spellings can differ.

Is the romanization perfect?

RTGS depends on syllable parsing and implicit vowels that are hard to resolve fully by machine. This tool applies the standard consonant and vowel values and is accurate for typical words, but complex spellings and silent letters may need a human check.

Thai to Latin Transliteration

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The Royal Thai General System of Transcription (RTGS) is Thailand’s official way of writing Thai words in the Latin alphabet — the spelling you see on road signs, maps, and government documents. This tool maps Thai script to RTGS using the correct consonant and vowel values.

How it works

Each Thai consonant has an RTGS value that differs between initial position (starting a syllable) and final position (closing it). For instance:

ส  initial = s   final = t
ช  initial = ch  final = t
ง  initial = ng  final = ng
ร  initial = r   final = n

Vowels are written above, below, before, or after the consonant they attach to, and RTGS renders them as a, e, i, o, u and digraphs such as ae, oe, ue. RTGS is a transcription: it deliberately drops tone marks and the long/short vowel distinction, so the output captures pronunciation in broad strokes rather than exact phonetics.

Example and tips

The word ไทย romanizes to thai, and กรุงเทพ (Bangkok’s Thai name) to krungthep. Because RTGS ignores tone and vowel length, distinct words can land on the same spelling — that is by design. For maps and official use this is exactly what you want; for language learning, pair it with a tool that also marks tones.