Foot calluses are caused primarily by repeated friction and pressure on specific areas of the feet. This friction often results from ill-fitting shoes that are too tight, too loose, or have high heels, which increase pressure on certain parts of the foot. Prolonged standing, poor foot support, obesity, and activities that put excessive rubbing or pressure on the feet also contribute to the formation of calluses. Additionally, age-related skin changes, genetics, and medical conditions like diabetes can increase the risk of developing calluses. Essentially, calluses form as a protective response by the skin to prevent damage from repeated irritation.