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Bulking calorie calculator — your surplus target.
This bulking calorie calculator tells you how many calories to eat each day to build muscle. It finds your maintenance calories with the Mifflin-St Jeor equation and your activity level, then adds a surplus — about 10 percent for a lean bulk or 20 percent for a standard bulk — and shows your protein target and expected weekly gain. Enter your details below — the result updates instantly, no signup.
Honest note: the weekly figure is scale weight, not pure muscle. Muscle is built at a fixed rate a bigger surplus cannot speed up — past about 10 to 20 percent over maintenance, extra calories become fat, not more muscle.
| Bulk type | Surplus | Daily calories | Weekly gain | What to expect |
|---|---|---|---|---|
| Lean bulk | +10% | — | — | ~0.25 kg/week, minimal fat gain, slower muscle |
| Standard bulk | +20% | — | — | ~0.5 kg/week, faster gain but more fat |
| Protein target | 1.6–2.2 g/kg | — | — | Protects and builds lean mass across the bulk |
Who a bulk is for.
- Hardgainers who struggle to gain weight and eat well below their true maintenance without a plan.
- Off-season lifters deliberately building muscle before a later cut or a physique push.
- Skinny beginners who need a consistent surplus and progressive overload to add their first serious muscle.
The bulking math, explained.
No black box. Maintenance from Mifflin-St Jeor, then a controlled surplus tied to your bulk type.
TDEE = BMR × activity Mifflin-St Jeor BMR — 10 × kg + 6.25 × cm − 5 × age + s — times 1.2 to 1.9 for activity gives maintenance calories.
target = TDEE × (1 + 10% or 20%) A lean bulk adds about 10 percent over maintenance; a standard bulk adds about 20 percent for faster gain.
1.6–2.2 g/kg · 7,700 kcal/kg Hit protein to build muscle; a kilo of tissue is roughly 7,700 kcal, so surplus ÷ 7,700 sets the weekly pace.
Worked example: a 30-year-old man, 178 cm and 80 kg, has a BMR of 1,768 calories. At a moderate activity factor of 1.55 his TDEE is about 2,740 calories. A lean bulk (+10%) lands near 3,015 calories, a standard bulk (+20%) near 3,290 calories. The 7,700-calorie-per-kilo rule is an average, and remember scale gain is not all muscle — track your weight for two to three weeks and ease the surplus if fat is climbing faster than strength.
Related nutrition calculators.
See the full picture — your maintenance line, the cut on the other side, and the macros behind the surplus.
TDEE calculator
Find the maintenance number every bulk builds on.
Open toolCutting calorie calculator
Flip to a deficit when the bulk is done.
Open toolMacro calculator
Split your bulking target into protein, carbs, and fat.
Open toolNutrition tracker
Log every meal against your surplus, in the browser.
Open toolBulking questions.
How many calories should I eat to bulk?
Start from your maintenance calories — your TDEE — and add a surplus. A lean bulk adds about 10 percent, and a standard bulk adds about 20 percent. For a moderately active man near 2,740 maintenance calories, that is roughly 3,015 calories a day for a lean bulk or 3,290 for a standard bulk. This calculator does that math from your details so you get an exact number instead of a generic "eat big".
What is a lean bulk vs a dirty bulk?
A lean bulk is a small, controlled surplus of about 10 percent over maintenance, aimed at gaining muscle with minimal fat — roughly 0.25 kg a week. A dirty bulk means eating with little regard for the size of the surplus, gaining weight fast but adding a lot of fat you later have to cut. A standard bulk at about 20 percent sits in between: quicker weight gain than a lean bulk, but more of it is fat.
How much of a surplus do I need to build muscle?
Less than most people think. Muscle is built at a fixed maximum rate that a larger surplus does not speed up, so once you are eating enough to support training, extra calories mostly become body fat. A surplus of about 10 to 20 percent over maintenance covers muscle growth for nearly everyone. Going far above that adds fat, not muscle.
How fast should I gain weight while bulking?
For most lifters past the beginner stage, about 0.25 to 0.5 kg per week is the sensible range — closer to 0.25 kg on a lean bulk. Faster than roughly 0.5 kg a week and a growing share of the gain is fat rather than muscle. Beginners and true hardgainers can push the upper end; experienced lifters should stay conservative to keep the bulk lean.
How much protein do I need when bulking?
Aim for about 1.6 to 2.2 grams of protein per kilogram of bodyweight per day. A 2018 meta-analysis in the British Journal of Sports Medicine found muscle-building benefits plateau near 1.6 g/kg, so that is a strong floor; the 2.2 g/kg upper end adds a safety margin. For an 80 kg lifter that is roughly 128 to 176 grams of protein a day, spread across meals.
Will eating more calories build muscle faster?
No — past a modest surplus, extra calories build fat, not muscle. Muscle protein synthesis has a ceiling set by training, recovery, and your genetics, and no amount of extra food raises that ceiling. That is the honest limit of bulking: a bigger surplus buys faster scale weight, most of which is fat you will cut later. Stay near 10 to 20 percent over maintenance and let time and progressive overload do the work.
Save your surplus. Hit it daily.
Free in your browser — Nishaana holds your bulking target and logs every meal against it, so you always know if you are eating enough to grow.
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