Weight Gain Calculator
Enter your current weight, goal weight, and a timeframe to see the weekly gain rate and daily calorie surplus needed to reach your goal.
Your calculation is performed in your browser.This result is an estimate for informational and educational purposes. It isn’t a diagnosis and isn’t a substitute for advice from a doctor, registered dietitian, or other qualified professional. See our methodology and sources for the formula used and its limitations.
How it works
The calculator divides the total weight you want to gain by your chosen timeframe to find the required weekly gain rate, then converts that rate into a daily calorie surplus using the standard energy value of body tissue gain. It flags timeframes that would require an unusually fast rate of gain.
Formula & methodology
Weekly rate = (goal weight − current weight) ÷ weeks. Daily surplus = (weekly rate × calories per unit of weight) ÷ 7.
Worked example
Gaining 6 kg over 24 weeks requires a rate of 0.25 kg per week, which needs a daily calorie surplus of about 275 calories.
Important notes
- —The calculator will not accept a timeframe that requires gaining more than 1 kg (about 2.2 lb) per week, since faster gains tend to add proportionally more fat than lean mass.
- —Pairing a calorie surplus with resistance training generally leads to a higher proportion of the gain being muscle rather than fat.