Weight classes are divisions of competition used to match competitors against others of their own size. Weight classes are used in a variety of sports, especially combat sports^[1] (such as boxing, kickboxing, mixed martial arts and wrestling). Alternatives to formal weight classes include catch weight and openweight.

The existence of weight divisions gives rise to the practice of weight cutting. To be the largest individual in a weight division is perceived as advantageous; therefore some athletes will work to lose weight through dieting and dehydration prior to weigh-ins to qualify for a lower weight class.^[2]