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Muay Thai Weight Classes: The Complete 2026 Guide

Every Muay Thai division across WBC, ONE Championship, and Thailand's legendary Lumpinee and Rajadamnern stadiums. Weight limits in pounds and kilograms, how they compare to boxing, and how weigh-in rules differ between traditional and modern promotions.

WBC Divisions
17
ONE Men's
5
Lightest
105
lbs (Minimumweight)
Heaviest
200+
lbs (WBC Heavyweight)

WBC Muay Thai Weight Classes

The World Boxing Council's Muay Thai division (WBC Muaythai) is the most internationally recognized sanctioning body for professional Muay Thai. It uses the same 17 weight classes and limits as professional boxing.

DivisionUpper Limit (lbs)Upper Limit (kg)
Minimumweight105 lbs47.6 kg
Light Flyweight108 lbs49 kg
Flyweight112 lbs50.8 kg
Super Flyweight115 lbs52.2 kg
Bantamweight118 lbs53.5 kg
Super Bantamweight122 lbs55.3 kg
Featherweight126 lbs57.2 kg
Super Featherweight130 lbs59 kg
Lightweight135 lbs61.2 kg
Super Lightweight140 lbs63.5 kg
Welterweight147 lbs66.7 kg
Super Welterweight154 lbs69.9 kg
Middleweight160 lbs72.6 kg
Super Middleweight168 lbs76.2 kg
Light Heavyweight175 lbs79.4 kg
Cruiserweight200 lbs90.7 kg
Heavyweight200 lbs+ (91 kg+) — no upper limit—

ONE Championship Muay Thai Weight Classes

ONE Championship is the largest martial arts organization in Asia and one of the biggest globally. Its Muay Thai roster uses fewer, wider divisions than traditional Muay Thai, with strict hydration testing to prevent dangerous weight cuts.

Men's Divisions

DivisionUpper Limit (lbs)Upper Limit (kg)
Strawweight125 lbs56.7 kg
Flyweight135 lbs61.2 kg
Bantamweight145 lbs65.8 kg
Featherweight155 lbs70.3 kg
Lightweight170 lbs77.1 kg

Women's Divisions

DivisionUpper Limit (lbs)Upper Limit (kg)
Atomweight115 lbs52.2 kg
Strawweight125 lbs56.7 kg

Lumpinee Stadium Weight Classes

Lumpinee Boxing Stadium in Bangkok is run by the Royal Thai Army and is the most prestigious venue in professional Muay Thai. It uses "Junior" divisions between standard weight classes, creating more granularity for Thai fighters who often compete at very light weights.

DivisionUpper Limit (lbs)Upper Limit (kg)
Mini Flyweight105 lbs47.6 kg
Junior Flyweight108 lbs49 kg
Flyweight112 lbs50.8 kg
Junior Bantamweight115 lbs52.2 kg
Bantamweight118 lbs53.5 kg
Junior Featherweight122 lbs55.3 kg
Featherweight126 lbs57.2 kg
Junior Lightweight130 lbs59 kg
Lightweight135 lbs61.2 kg
Junior Welterweight140 lbs63.5 kg
Welterweight147 lbs66.7 kg
Junior Middleweight156 lbs70.8 kg
Middleweight160 lbs72.6 kg
Junior Heavyweight175 lbs79.4 kg
Heavyweight175 lbs+ (79.4 kg+) — no upper limit—

Junior divisions bridge the gap between standard classes. For example, Junior Welterweight at 140 lbs sits between Lightweight (135) and Welterweight (147). Lumpinee does not regularly host bouts above Junior Heavyweight (175 lbs).

Muay Thai vs Boxing: Weight Class Comparison

WBC Muay Thai and professional boxing share identical weight limits — a WBC Muay Thai welterweight and a boxing welterweight both top out at 147 lbs. But ONE Championship Muay Thai diverges dramatically.

Division NameWBC Muay ThaiONE Muay ThaiBoxing
Flyweight112 lbs135 lbs112 lbs
Bantamweight118 lbs145 lbs118 lbs
Featherweight126 lbs155 lbs126 lbs
Lightweight135 lbs170 lbs135 lbs
Welterweight147 lbs—147 lbs

The most striking difference is ONE's Flyweight at 135 lbs — the same as boxing's Lightweight division. A boxer who fights at 135 lbs (lightweight) would be a Flyweight in ONE Championship. This naming mismatch confuses many fans crossing over from boxing to Muay Thai.

Muay Thai Weigh-In Rules

Weigh-in rules vary significantly between traditional Thai stadiums and modern international promotions.

Thai Stadium Weigh-Ins: Lumpinee and Rajadamnern traditionally weigh fighters on the morning of the fight, leaving minimal time for rehydration. This discourages extreme weight cuts because fighters must compete soon after weighing in. Fighters who miss weight may face purse deductions or cancellation, though enforcement varies by promoter.

WBC Muay Thai Weigh-Ins: Following boxing conventions, WBC Muay Thai holds official weigh-ins the day before the fight. Fighters have 24+ hours to rehydrate. Missing weight results in a purse penalty and the bout becomes a non-title contest if a belt was on the line.

ONE Championship Weigh-Ins: ONE uses the most athlete-protective system in combat sports. Fighters must pass both a weight check and a urine-specific gravity hydration test. This prevents extreme dehydration — if a fighter is too dehydrated, they cannot compete regardless of whether they hit the scale number. Fighters who fail are moved to a higher weight class or removed from the card.

Frequently Asked Questions

It depends on the organization. WBC Muay Thai recognizes 17 divisions, matching professional boxing from Minimumweight (105 lbs) to Heavyweight (200+ lbs). ONE Championship uses 5 men's and 2 women's divisions. Traditional Thai stadiums like Lumpinee and Rajadamnern typically use 13–15 divisions, with Lumpinee adding 'Junior' classes between standard divisions.

WBC Muay Thai follows the exact same weight limits as professional boxing. However, ONE Championship Muay Thai uses completely different limits — for example, ONE's Flyweight is 135 lbs while boxing's Flyweight is only 112 lbs, a 23-pound difference. If you are a boxer moving to ONE Championship Muay Thai, you would likely fight in a different-named division.

The lightest division is Minimumweight (also called Mini Flyweight), with an upper limit of 105 lbs (47.6 kg). This is the same across WBC Muay Thai, Lumpinee, Rajadamnern, and WMC. ONE Championship does not currently have a division this light — its smallest women's class is Atomweight at 115 lbs.

Both historic Bangkok stadiums use similar weight structures, but Lumpinee adds 'Junior' divisions between standard classes (e.g., Junior Welterweight at 140 lbs between Lightweight at 135 and Welterweight at 147). Rajadamnern does not use these Junior labels. Lumpinee's heavyweight threshold starts at 175 lbs, while Rajadamnern does not regularly host heavyweight bouts, capping around 160 lbs (Middleweight).

ONE Championship uses a much smaller number of divisions than traditional Muay Thai — just 5 for men and 2 for women. Their weight limits are also significantly higher than boxing equivalents with the same name. For example, a ONE Featherweight can weigh up to 155 lbs, while a boxing featherweight tops out at 126 lbs. ONE also enforces strict hydration testing, meaning fighters cannot simply dehydrate to make weight.

Yes, but it is smaller. In WBC Muay Thai, heavyweight starts at 200 lbs (91 kg), the same as boxing. However, elite Muay Thai heavyweights rarely exceed 230 lbs, whereas boxing heavyweights regularly hit 240–270+ lbs. Lumpinee's heavyweight division starts much lower at 175 lbs. There are far fewer high-level heavyweights in Muay Thai compared to boxing.

Traditional Thai stadium fights typically weigh in on the morning of the event, giving fighters less time to rehydrate than boxing or MMA. In international promotions like ONE Championship, fighters must pass both a weight check and a hydration test, preventing extreme dehydration. WBC Muay Thai generally follows boxing-style weigh-ins the day before the fight.

Yes, though it is less common than in boxing due to the thinner talent pool in some divisions. Saenchai is perhaps the most famous example, competing across multiple weights from 115 lbs to 147 lbs. In ONE Championship, Rodtang Jitmuangnon has dominated the Flyweight division, and several fighters have moved between Muay Thai and kickboxing divisions within the same promotion.
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