Calorie calculator · Muscle gain
How many calories to build muscle?
Work out your calorie target for the bulk: TDEE plus a controlled surplus — enough for muscle growth without piling on unnecessary fat.
Your calorie target for the bulk
And who's going to count that every day?
Myron tracks your calorie target for you — you speak, the AI logs. "Scrambled eggs from three eggs and two slices of whole-grain bread" is all it takes.
How this calculator works
It's built on the Mifflin-St Jeor equation, which estimates your basal metabolic rate from weight, height, age and sex — the most reliable of the common formulas in comparison studies. Your BMR is multiplied by your activity factor (PAL) to get your total daily energy expenditure. Depending on your goal, the calculator subtracts a moderate deficit or adds a surplus — converted at ~7,700 kcal per kilogram of body mass.
| Activity level | Factor |
|---|---|
| Sedentary, little training | 1.2 |
| Lightly active | 1.375 |
| Moderately active | 1.55 |
| Very active | 1.725 |
| Extremely active | 1.9 |
The macro recommendation follows sports science instead of rigid percentages: protein by body weight and goal (1.8–2.4 g/kg), fat as a baseline (0.9 g/kg), and the rest goes to carbs — your fuel for training.
Frequently asked questions
How many calories do I need to build muscle?
A slight surplus of about 150–300 kcal above your TDEE is enough — building muscle is a slow process. A big surplus mostly accelerates fat gain, not muscle growth.
How much protein do I need to build muscle?
About 1.6–2.2 g of protein per kg of body weight per day is well supported; the calculator uses 1.8 g/kg for bulking. The daily total matters more than perfect timing.
Can I build muscle and lose fat at the same time?
As a beginner, after a long break, or at a higher body-fat percentage: yes — body recomposition works at maintenance with plenty of protein and progressive strength training. Advanced lifters usually do better with separate bulking and cutting phases.
Formula: Mifflin MD, St Jeor ST et al. (1990): A new predictive equation for resting energy expenditure in healthy individuals — more under Methodology & data sources. More to look up: calorie tables · exercise directory.