Calories to Gain a Pound Calculator

About this calculator

This calculator is built on the long-standing rule of thumb that one pound of body weight is roughly equal to a 3,500-calorie surplus, since a pound of stored fat contains about that much energy. Enter how many pounds you want to gain and it multiplies that by 3,500 to get your total calorie target, then divides it by your planned daily surplus to estimate how many days it will take.

Dietitians and fitness trainers use this figure — alongside a person's maintenance calories from a TDEE calculation — to build gradual, sustainable bulking or weight-gain plans, typically targeting a 250–500 calorie daily surplus for slow, mostly-lean gains rather than a large surplus that adds excess fat.