Thai Tone Rule Explainer

Show the tone calculation rules for any Thai syllable you type

For each Thai syllable typed, determines which of the five tones applies based on initial consonant class, vowel length, final consonant (live or dead), and any tone mark.

What determines a Thai syllable's tone?

Four things combine: the class of the initial consonant (high, mid, or low), whether the syllable is live or dead, the length of the vowel, and any tone mark written above it. Thai has no separate 'tone letters' — the tone is computed from these features.

Thai is a tonal language with five tones — mid, low, falling, high, and rising — but it has no dedicated tone letters. Instead, the tone of a syllable is calculated from four features: the class of the initial consonant, whether the syllable is live or dead, the vowel length, and any tone mark written above. This tool takes a Thai syllable, identifies each of those factors, and reports the resulting tone with the rule it applied.

How it works

The tone is derived in steps:

  1. Consonant class of the initial — mid (e.g. ก จ ด ต บ ป อ), high (e.g. ข ฉ ถ ผ ฝ ส ห), or low (the majority).
  2. Live vs dead syllable — live ends in a long vowel or a sonorant final (ม น ง ย ว ญ ร ล); dead ends in a short vowel with no final or in a stop final (ก/ด/บ sounds).
  3. Vowel length — matters for dead syllables on low-class initials.
  4. Tone markmai ek , mai tho , mai tri , mai chattawa — overrides the default, with the result depending on the consonant class.

For an unmarked syllable, the default tone follows a class-and-live/dead table: e.g. a mid-class live syllable is mid tone, a high-class dead syllable is low tone, a low-class live syllable is mid tone.

Example and notes

The word ข้าว (khâao, “rice”) starts with ข (high class), is live (long vowel า plus final ว), and carries mai tho . Mai tho on a high-class initial yields the falling tone — hence khâao. Without the mark, high-class live default would be rising (khǎao). The tool walks through exactly these factors so you can see why a syllable carries the tone it does, not just what the tone is.