What are the age groups and weight classes in Muay Thai?
I · Intermediate · The contest · 1 of 4Age category is set by year of birth: U8 to U16 in two-year bands, U18 (16 and 17), U24 (18 to 23), Elite (18 to 40) and Masters from 35. Elite men have 14 weight classes from 45 to over 91 kg, women 11 from 45 to over 75 kg. Athletes are weighed each morning they fight, once only.
How it works
- Age: the age reached by 31 December of the competition year.
- Pathways: Elite, Development (U groups) or Masters; one per competition.
- Elite men: 45 to over 91 kg; the 45 kg class only at some multi-sport events.
- Elite women: 45 to over 75 kg.
- Weigh-in: each competition morning, after a medical check.
- One attempt: the first weight recorded is final.
- Missing or failing: a loss by walkover.
- Pre-contest check: 5 per cent over the class is disqualification.
The glossary has the age categories (Muay Thai), the weight classes (Muay Thai), the weigh-in (Muay Thai), the Khan, the walkover (Muay Thai) and the disqualification (Muay Thai).
Tricky cases
A 17-year-old turns 18 in December. Which group?
Elite or U24 for that whole year, as age is set by 31 December.
An athlete misses weight by 0.2 kg. Another try?
No. Only one attempt a day.
Can a travel-delayed U24 athlete get an allowance?
Yes, 0.5 kg if the Technical Delegate agrees, but they must make weight before their first contest.
What Khan level do elite athletes need?
At least Khan 6.
Why the rule exists
Matching athletes by age and weight keeps fights fair and safer. A single, final weigh-in stops athletes cutting weight in stages.
Where it differs
| Where | What changes | Source |
|---|---|---|
| Elite and U24 | Same weight classes | 4 |
| U18 | Women from 42 kg | 4 |
| Masters 40+ and 45+ | No over-91 kg class | 4 |
From the rule book
IFMA, Rules & Regulations for International Competition, version 3.057, rules 4, 5, 6 and 11. Checked 14 October 2026. Official document: the IFMA Rules & Regulations, version 3.057.