How big should your calorie surplus be?
Eat more than you burn and you give your body the energy to build muscle. Past a certain point, the extra food turns into fat, because muscle only grows so fast.
A 2019 review of nutrition for natural bodybuilders recommends 10 to 20% above maintenance for novice and intermediate lifters, and 5 to 10% for advanced lifters. This calculator gives you two settings inside that range.
| Goal | Surplus | Expected gain a week | For the example (82 kg) |
|---|---|---|---|
| Build muscle, lean | +10% | 0.25% of body weight | About 0.2 kg |
| Build muscle, standard | +15% | 0.4% of body weight | About 0.3 kg |
Pick lean if you have been lifting for years or you want to stay close to your current body fat. Pick standard if you are newer to lifting or struggling to gain.
A worked example
This is the example filled in above: a 24-year-old man, 178 cm and 82 kg, on his feet some of the day, lifting four times a week.
| Step | Sum | Result |
|---|---|---|
| Burned at rest | (10 × 82) + (6.25 × 178) − (5 × 24) + 5 | 1,817.5 kcal |
| Add daily activity | 1,817.5 × 1.375 | 2,499 kcal |
| Add four gym sessions | 4 × 250 ÷ 7 | 2,642 kcal |
| Add a 15% surplus | 2,642 × 1.15 | 3,040 kcal, to the nearest 10 |
| Protein | 82 × 1.8 g | 148 g |
| Fat | 25% of 3,040 kcal ÷ 9 | 84 g |
| Carbs | (3,040 − 592 − 756) ÷ 4 | 423 g |
On the lean setting, the same person eats 2,910 kcal: 148 g of protein, 397 g of carbs and 81 g of fat.
The macro calculator goes through every step in more detail, including the activity levels and how the minimum calorie limits work.
How fast should your weight go up?
The same review suggests aiming for 0.25 to 0.5% of your body weight a week, or around 0.25% if you are an advanced lifter.
| Body weight | 0.25% a week | 0.5% a week |
|---|---|---|
| 70 kg | 0.18 kg | 0.35 kg |
| 80 kg | 0.2 kg | 0.4 kg |
| 90 kg | 0.23 kg | 0.45 kg |
| 100 kg | 0.25 kg | 0.5 kg |
Water, salt and the food in your gut can move your weight by a kilo from one morning to the next. Weigh in a few mornings a week and compare weekly averages.
When to change your calories
Give any new target two full weeks before you change it, and check that you have been eating it. Food you planned and skipped is the most common reason a bulk stalls.
- The weekly average isn't rising: add about 5% to your calories.
- It's rising faster than 0.5% a week: take off about 5%.
- It's on pace: leave everything alone.
Liftprep makes this check for you. Log your weight a few times a week, and it moves your target by 5% when you have stayed off pace for two weeks and eaten at least 70% of your planned meals.
Common questions
How many calories should I eat to bulk?
Start 10 to 15% above your maintenance calories. For someone who burns 2,640 kcal a day, that means 2,910 to 3,040 kcal. Your maintenance depends on your size, your daily activity and your gym sessions, which is what the calculator works out.
How much weight should I gain a week on a bulk?
Aim for 0.25 to 0.5% of your body weight a week. That is 0.2 to 0.4 kg a week at 80 kg. Advanced lifters should stay near 0.25%.
Why is protein lower here than on a cut?
This calculator sets 1.8 g per kg on a bulk and 2.2 g per kg on a cut. Extra calories make it easier for your body to keep muscle, so protein can come down and carbs can fuel your training. Both figures sit inside the 1.6 to 2.2 g per kg range recommended for people who lift.
What is a dirty bulk?
A dirty bulk means eating as much as you can with no target. Your muscle can only grow so fast, so most of the extra weight comes on as fat, and you then have to diet it off.
Can I use stone and pounds?
The calculator takes kg and cm. To convert, multiply stone by 6.35 and pounds by 0.45, so 13 stone is about 82.6 kg. Multiply feet by 30.5 and inches by 2.54, so 5 ft 10 is about 178 cm.
Does the calculator save what I type?
No. The sums run in your browser and your age, height and weight stay on your device. Our website statistics record only that the calculator was used, the goal picked and the calories shown. The privacy policy has the details.
Is it free?
Yes. You don't need an account or an email address to use it.
Sources
- Iraki J, Fitschen P, Espinar S, Helms E (2019). Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports 7(7): 154.
- Morton RW et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine 52: 376–384.
- Mifflin MD et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition 51: 241–247.