📈 Weight Gain Calculator
Estimate the daily calorie surplus you need above maintenance to gain a target amount of weight over a chosen timeframe.
How weight gain works
Gaining weight requires consistently eating more calories than your body burns (a calorie surplus). The size of the surplus and how long you maintain it determine how much weight you gain and how quickly.
The formula
This calculator uses the widely referenced estimate that approximately 3,500 kilocalories equal one pound of body weight. It multiplies your target weight gain by 3,500, divides by the number of days in your timeframe to get a daily surplus, then adds that to your maintenance calories for a daily target.
The 3,500-calorie rule is a simplified estimate; actual weight gain also depends on factors like body composition, activity, and whether the gain is fat or muscle. This tool is for general planning purposes only and is not a substitute for guidance from a registered dietitian or physician.