• Mini Flyweight - from 100lb / 45.454kg and not over 105lb / 47.727kg
• Light Flyweight - from 105lb / 47.728kg and not over 108lb / 48.988kg
• Flyweight - from 108lb / 48.989kg and not over 112lb / 50.802kg
• Super Flyweight - from 112lb / 50.803kg and not over 115lb / 52.163kg
• Bantamweight - from 115lb / 52.164kg and not over 118lb / 53.524kg
• Super Bantamweight - from 118lb / 53.525kg and not over 122lb / 55.338kg
• Featherweight - from 122lb / 55.339kg and not over 126lb / 57.153kg
• Super Featherweight - from 126lb / 57.154kg and not over 130lb / 58.967kg
• Lightweight - from 130lb / 58.968kg and not over 135lb / 61.235kg
• Super Lightweight - from 135lb / 61.236kg and not over 140lb / 63.503kg
• Welterweight - from 140lb / 63.504kg and not over 147lb / 66.678kg
• Super Welterweight - from 147lb / 66.679kg and not over 154lb / 69.853kg
• Middleweight - from 154lb / 69.854kg and not over 160lb / 71.575kg
• Super Middleweight - from 160lb / 71.576kg and not over 168lb / 76.204kg
• Light Heavyweight - from 168lb / 76.205kg and not over 175lb / 79.379kg
• Cruiseweight - from 175lb / 79.380kg and not over 190lb / 86.183kg
• Heavyweight - from 190lb / 86.184kg 
  

Muaythai techniques were known as the "Art of Eight Limbs" as there are eight natural weapons to fight with: fists, elbows, knees and feet. The most peculiar muaythai techniques, which also differentiate Thai boxing from Chinese and Japanese martial arts, are related to the use of elbows and knees to ultimately destroy the opponent. The risk of injuries from such blows is quite high, therefore in many international tournaments elbows strikes are banned, penalizing Thai fighters when matched against foreign champions. Even in Thailand, some beautiful and vicious elbow/knees combinations are rarely used, or forbidden, as muaythai itself is evolving into a less pure form of traditional Thai boxing.