Weight Gain Calculator
If you want to gain weight healthily without piling on excess fat, enter your current weight, target weight, and how long you want it to take — you'll get the daily calorie surplus you need.
Your Result
Add this surplus to your daily maintenance calories, which you can calculate with the daily calorie calculator.
This calculator gives general estimates for informational purposes only and does not replace advice from a doctor or sports nutritionist.
How is weight gain calculated?
Gaining one kilogram of body weight requires roughly 7,700 extra calories accumulated over time. We take the difference between your current and target weight, multiply it by 7,700, then divide by the number of days in your chosen timeframe to get the required daily surplus.
Add this surplus to your daily maintenance calories (TDEE) — calculate that with the calorie calculator — to get your total daily calorie target.
Tips for healthy weight gain
- Avoid a surplus that's too large (over 500-700 kcal/day) so you don't gain fat faster than muscle.
- Eat enough protein (1.6-2.2g per kg of body weight) to make sure the gain goes toward muscle, not just fat.
- Lift weights regularly — a calorie surplus without resistance training usually leads to fat gain rather than muscle.
- Track your weight weekly and adjust calories if your rate of gain is slower or faster than expected.