Free calculator
Bulking calorie calculator
Estimate a controlled calorie surplus and daily macros for building muscle. Choose the surplus instead of letting a black-box formula choose it for you.
Your starting point
Estimated daily target
- Protein
- 127g
- Fat
- 83g
- Carbs
- 436g
- Estimated maintenance
- 2,728 kcal
- Estimated resting needs
- 1,760 kcal
- Daily adjustment
- +10%
Treat this as a starting estimate. Track your average body weight for 2 to 3 weeks, then adjust calories in small steps if your trend does not match your goal.
How it works
Start controlled. Calibrate with data.
The calculator estimates resting energy expenditure with the Mifflin-St Jeor equation and applies your selected activity level. It then adds 5%, 10%, or 15% to estimated maintenance.
A 2022 review notes that sports nutrition guidance commonly recommends roughly 300 to 500 extra calories per day for intentional weight gain, but also highlights the limited evidence behind a universal prescription. Percentage options make the starting surplus scale with estimated energy needs, while your weight trend tells you whether it fits.
Protein is set at 1.6 g/kg/day. Fat receives 25% of calories, inside the National Academies adult range of 20% to 35%, and carbohydrate receives the remaining calories.
Sources and limitations
- 1. Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990.
- 2. Slater GJ et al. Weight gain recommendations for athletes and military personnel. Current Nutrition Reports, 2022.
- 3. Morton RW et al. Protein supplementation and resistance training meta-analysis. British Journal of Sports Medicine, 2018.
- 4. National Academies. Acceptable Macronutrient Distribution Ranges for adult fat and carbohydrate intake.
This calculator is for generally healthy adults ages 19 to 78. It is not medical advice and is not intended for pregnancy, breastfeeding, eating disorders, or medical nutrition therapy. Predictive equations can differ from measured energy needs. For a dynamic weight-change model, see the NIH Body Weight Planner or speak with a registered dietitian.
Bulking calculator FAQ
How many calories should I eat to bulk?
Start with estimated maintenance plus a controlled surplus. This calculator offers 5%, 10%, and 15% options because no single surplus has been validated as optimal for every lifter.
Is a 500-calorie surplus necessary to build muscle?
No. Sports nutrition guidance often mentions 300 to 500 extra calories per day, but research has not established one universal sweet spot. Training age, body size, appetite, and the rate of weight change all matter.
How should I adjust my bulking calories?
Keep intake consistent, weigh under similar conditions, and compare weekly averages for 2 to 3 weeks. If weight is flat, add a small amount. If it rises faster than intended, remove a small amount.
Trying to gain muscle while reducing body fat? Use the body recomposition calculator.
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