What a calorie surplus is
It means eating a little more than you burn, and this calorie surplus calculator sets that margin for your bulking phase. The extra supplies the energy and building materials for new muscle, as long as there is a training stimulus that calls for it. Without strength training, a surplus only adds fat.
How big a surplus to use
The review by Iraki and colleagues (2019) on off-season nutrition recommends a surplus of around 10-20% and gaining between 0.25 and 0.5% of body weight per week for beginners and intermediates, with a more conservative surplus for advanced lifters. The calculator offers three levels:
| Level | Surplus | Who it is for |
|---|---|---|
| Lean | +5% | Advanced lifters, who already build muscle slowly |
| Standard | +10% | The default option for most people |
| Beginner | +15% | First year of training, when muscle grows fastest |
Do you need a surplus to build muscle?
Not always, but it helps. The review by Slater and colleagues (2019) concluded that the exact surplus needed to maximize hypertrophy is unknown, although there is clear evidence that an energy surplus supports muscle growth. For beginners or people with a fair amount of body fat, body recomposition can be an alternative.
How much muscle you can expect
Beyond a certain point, more calories do not mean more muscle: the rate at which tissue is built is limited, and the excess is stored as fat. That is why a moderate surplus usually works better than "eating as much as possible". We explain it with numbers in how much muscle you can gain per month and in the diet for building muscle.
Protein, on top of calories
The meta-analysis by Morton and colleagues (2018), covering 49 studies, found no further gain in lean mass above about 1.6 g of protein per kilo per day. Calculate your number with the protein calculator.
