What’s the purpose of weight classes in Muay Thai?
To make Muay Thai matches fairer, fighters are marched together by weight. This helps ensure that fighters are going to be roughly the same size.
This seems quite obvious but, everything else being equal, larger fighters are going to be able to hit harder than lighter fighters. They simply have more mass. Even if their punches travel at the same speed, they will deliver more force.
Fights between fighters of unequal weight would therefore be unbalanced. Larger fighters would be able to inflict more damage than the smaller fighter making it more likely that they would be able to land a knock out punch to win the fight.
I’ve written on a similar topic here – Does height matter in a fight?
Such one sided fights wouldn’t be particularly entertaining to watch as, generally speaking, it more interesting to see which is the more skillful fighter.
Fighters therefore compete against other fighters in the same weight category.
Weight divisions in Muay Thai Associations
Different Muay Thai Associations have different weight divisions.
United States Muaythai Federation (USMF)
Adult – Youth Male and Female
Pin Weight – 102 lbs and Under
Atom Weight- 102.1- 107 lbs
StrawWeight- 107.1- 112 lbs
Fly Weight – 112.1- 117 lbs
BantamWeight- 117.1- 122 lbs
Featherweight- 122.1- 127 lbs
Lightweight- 127.1 – 132 lbs
Super Lightweight- 132.1 – 137 lbs
Light Welter- 137.1 – 142 lbs
Welterweight- 142.1- 147 lbs
Super Welter- 147.1- 153 lbs
Light Middle- 153.1 – 159 lbs
Middleweight- 159.1- 165 lbs
Super Middle- 165.1- 172 lbs
Light HeavyWeight- 172.1- 179 lbs
Light Cruiser- 179.1- 186 lbs
Cruiser Weight- 186.1- 195 lbs
Heavy Weight- 195.1- 215 lbs
Super Heavy- 215.1 and Above lbs
Youth Male and Female Ages (10-17)
Youth PinWeight- 47 lbs and Under
Youth AtomWeight- 47.1- 52 lbs
Youth StrawWeight- 52.1- 57 lbs
Youth Flyweight- 57.1- 62 lbs
Youth Bantamweight- 62.1- 67 lbs
Youth Featherweight- 67.1- 72 lbs
Youth Lightweight- 72.1- 77 lbs
Youth Welter- 77.1 – 82 lbs
Youth Middle- 82.1- 87 lbs
Youth Cruiser- 87.1- 92 lbs
Youth Heavy- 92.1- 97 lbs
Kru Muaythai Association
Mini Flyweight – 105 lbs
Light Flyweight – 108 lbs
Flyweight – 112 lbs
Super Flyweight – 115 lbs
Bantamweight – 118 lbs
Super Bantamweight – 122 lbs
Featherweight – 126 lbs
Super Featherweight – 130 lbs
Lightweight – 135 lbs
Super Lightweight – 140 lbs
Welterweight – 147 lbs
Super Welterweight – 154 lbs
Middleweight – 160 lbs
Super Middleweight – 168 lbs
Light Heavyweight – 175 lbs
Cruiserweight – 200 lbs
Heavyweight – 265 lbs
World Muaythai Council
Mini Fly Weight – 105 lbs
Light-Fly Weight – 108 lbs
Fly Weight – 112 lbs
Super Fly Weight – 115 lbs
Bantam Weight – 118 lbs
Super Bantam Weight – 122 lbs
Feather Weight – 126 lbs
Super Feather Weight – 130 lbs
Light Weight – 135 lbs
Super Light Weight – 140 lbs
Welter Weight – 147 lbs
Super Welter Weight – 154 lbs
Middle Weight – 160 lbs
Super Middle Weight – 168 lbs
Light Heavy Weight – 175 lbs
Super Light Heavy Weight – 182 lbs
Cruiser Weight – 190 lbs
Heavy Weight – 209 lbs
Super Heavy Weight – 209+ lbs
When do boxers weigh-in before a fight?
The timing of the weigh-in varies between different Associations.
The World Muaythai Council dictates that the fighters must weigh-in no more than 24 hours before the actual fight. The weigh-in itself is done without clothes and just before, the fighters have a physical examination by a doctor to ensure they are physically fit enough to fight.
Contestants in United States Muaythai Federation are required to weigh-in on the morning of the competition or the day before the first competition day. There is a three hour window following the close of the weigh-in and the fight, although this time can be shortened by the officials. Male and female fighters complete the weigh-in wearing light underwear.
The Kru Muaythai Association specifies that fighters must weigh-in at least 3 hours before the fight. They are not permitted to wear clothes whilst they complete the weigh-in.
Related Reading
Muay Lao vs Muay Thai: is there a difference?
Bang Muay Thai: a new martial art style!
Can Muay Thai be used in a street fight?
Can you use elbows in Muay Thai?
What moves are illegal in Muay Thai?
23 Muay Thai techniques -beginner and advanced [with GIFS!]