Calorie surplus calculator for gaining muscle
The calculator works out how many calories to eat a day to gain weight without piling on fat: your daily burn plus 10% or 20%. It shows calories, protein, fat and carbs, and roughly how much to gain each week.
Track it every day in Telegram
Where the number comes from
The formula, a worked example and where it stops working
How many calories you need to bulk
To gain weight you have to eat more than you burn. First the calculator works out your daily burn: basal metabolism from the Mifflin-St Jeor equation, times an activity multiplier. That's your TDEE — at that level your weight holds steady. On top goes a surplus of 10% or 20%. That range comes from a review of nutrition advice for natural bodybuilders in the off-season. The same review sets the pace: gain 0.25-0.5% of body weight a week. Example: a 25-year-old man, 70 kg, 178 cm, training 3-5 times a week. His burn is 2,623 kcal. With a 10% surplus that's 2,885 kcal a day, with 20% it's 3,148. At his weight that means gaining roughly 0.18 to 0.35 kg a week. That sounds slow, and it's meant to: muscle grows more slowly than fat, and extra calories on top mostly end up as fat. Start at +10% and check your weekly average after two or three weeks.
Sources: the equation — Mifflin MD, St Jeor ST et al., American Journal of Clinical Nutrition, 1990; surplus and pace — Iraki J, Fitschen P, Espinar S, Helms E, Sports, 2019.
The worked example
Same man: 25, 70 kg, 178 cm, moderate activity. Here's what the calculator shows at each pace:
| Pace | Burn (TDEE) | Calories | Surplus | Protein | Fat | Carbs |
|---|---|---|---|---|---|---|
| +10% | 2,623 | 2,885 | +262 | 140 g | 80 g | 401 g |
| +20% | 2,623 | 3,148 | +525 | 140 g | 87 g | 451 g |
Man, 25, 70 kg, 178 cm, moderate activity (×1.55).
What 0.25-0.5% of body weight a week means
The figure comes from the 2019 review by Iraki and colleagues, and it's meant for novice and intermediate bodybuilders. For people who have trained for years, the authors suggest being even more cautious with both the surplus and the pace. At 70 kg, 0.25-0.5% is 0.18-0.35 kg a week, or roughly 0.7-1.4 kg a month.
Day-to-day weight swings more than that: water, salt, what's in your gut. So don't go by a single morning — look at the weekly average. If it's rising within that range, your pace is right.
How much protein you need when bulking
The International Society of Sports Nutrition (ISSN), in its 2017 position stand, puts protein for most people who exercise at 1.4-2.0 g per kilogram of body weight a day (Jäger R et al., JISSN, 2017). The calculator takes the top of that range, 2 g/kg: 140 g a day at 70 kg.
Fat is set at a quarter of calories and everything else goes to carbs, which fuel your training. It's a starting split, not a hard rule: if you prefer more fat and fewer carbs, your calories stay the same. More on protein in how much protein you need per day; the protein calculator works out a target for your goal.
Bulking calories by weight
How much to eat at different weights. Age, height and activity are fixed and listed under the table — enter your own details above for your numbers.
| Weight | Burn (TDEE) | +10% | +20% | Gain per week |
|---|---|---|---|---|
| 50 kg | 2,018 | 2,220 | 2,422 | +0.13–0.25 kg |
| 60 kg | 2,155 | 2,371 | 2,586 | +0.15–0.30 kg |
| 70 kg | 2,293 | 2,522 | 2,752 | +0.18–0.35 kg |
| 80 kg | 2,430 | 2,673 | 2,916 | +0.20–0.40 kg |
| 90 kg | 2,568 | 2,825 | 3,082 | +0.23–0.45 kg |
| 100 kg | 2,705 | 2,976 | 3,246 | +0.25–0.50 kg |
Man, 30, 178 cm, light activity (×1.375). Gain is 0.25-0.5% of body weight per week.
The same for women
The equation accounts for sex: at the same weight, women usually burn less, so the bulking target comes out lower. The surplus percentages and the pace are the same.
| Weight | Burn (TDEE) | +10% | +20% | Gain per week |
|---|---|---|---|---|
| 50 kg | 1,678 | 1,846 | 2,014 | +0.13–0.25 kg |
| 60 kg | 1,815 | 1,997 | 2,178 | +0.15–0.30 kg |
| 70 kg | 1,953 | 2,148 | 2,344 | +0.18–0.35 kg |
| 80 kg | 2,090 | 2,299 | 2,508 | +0.20–0.40 kg |
| 90 kg | 2,228 | 2,451 | 2,674 | +0.23–0.45 kg |
| 100 kg | 2,365 | 2,602 | 2,838 | +0.25–0.50 kg |
Woman, 30, 165 cm, light activity (×1.375). Gain is 0.25-0.5% of body weight per week.
Why a dirty bulk doesn't build muscle faster
The temptation makes sense: eat everything, the scale climbs fast, so the muscle must be growing too. But muscle grows at its own speed, set by training, sleep and protein, not by an extra thousand calories. Anything beyond what you need gets stored as fat. Later you'll have to cut that fat on a deficit, and part of the time is wasted.
That's why the surplus here is modest. In the macro calculator, the "Gain" goal adds 300 kcal — with a typical burn of 2,000-3,000 kcal that's about 10-15% on top, the same range. The macro calculator is fine if you just need a split; use this one if you want to pick a pace and see the expected gain.
How to eat more when you're not hungry
For a lot of people trying to gain, the problem isn't knowing the target but actually eating it. An extra 300-500 kcal a day sounds modest until you try.
- Add a meal rather than making every plate bigger: four meals a day are easier than three huge ones
- Go for calorie-dense food: nuts, peanut butter, cheese, grains, bread, a drizzle of oil on salads and porridge
- Drink some of your calories: milk, kefir, yogurt, a smoothie with banana and oats fill you up less than the same food on a plate
- Keep a snack within reach — at work, in your bag, in the car
- Don't fill up on water right before a meal: eat first, drink after
What to do if the scale won't move
- Check you're really eating the calculator's number every day, not just on training days
- Look at the average over two or three weeks, not a single weigh-in
- If that average hasn't gone up, move from +10% to +20%
- Recalculate once you've gained 3-4 kg: your burn goes up too, so the old surplus shrinks. The TDEE calculator is handy for checking it
- If you still don't gain at +20% and you're sure of your counting, see a doctor
Bulking breaks in the same place as dieting: on days you ate less than you thought. To see the real numbers, there's a bot that counts calories and macros from a photo — it remembers your target and shows how much is left to eat today.
Frequently asked questions
How many calories do I need to build muscle?
Your daily burn plus 10-20%. For example, a 25-year-old man at 70 kg and 178 cm who trains 3-5 times a week needs about 2,885 kcal at +10% and 3,148 kcal at +20%. The calculator above works out your own number.
How big should my calorie surplus be?
A review of advice for natural bodybuilders (Iraki et al., 2019) suggests about 10-20% above your burn. Start at 10% to keep extra fat down. If your weight doesn't go up in two or three weeks, move to 20%.
How much protein do I need when bulking?
The ISSN puts it at 1.4-2.0 g per kilogram of body weight a day for people who exercise. The calculator uses 2 g/kg, which is 140 g at 70 kg.
How fast can I gain weight?
The target for novice and intermediate lifters is 0.25-0.5% of body weight a week. At 70 kg that's 0.18-0.35 kg. Faster usually means more fat, not more muscle.
Are bulking macros different for women?
The equation accounts for sex, so a woman's calories at the same weight come out lower. The surplus percentages, protein per kilogram and weekly pace are the same.
What if I'm not gaining weight on a surplus?
First check you eat the target every day, and look at the average over two or three weeks. If it isn't rising, move to +20% and recalculate for your new weight. If that doesn't help either, see a doctor.
Reminders
Water and weight