The number of inches a corset can take off will vary depending on the individual and the type of corset they are wearing. Corsets work by applying pressure to the waist and hips, which can temporarily reduce the size of the waistline. However, the amount of reduction will depend on several factors, including the fit of the corset, the body type of the person wearing the corset, and the length of time the corset is worn. In general, a corset can take off several inches from the waistline, but the exact amount will vary depending on the individual.