Bulking Macro Calculator
Turn your calorie target into exact protein, carb, and fat grams.
This is educational content, not medical advice. Talk with your doctor before changing your diet, exercise, or supplements, especially for teens, adults over 65, or anyone managing a health condition or taking medication. Full medical disclaimer.
How the split works
Macros are decided in order of importance, and this calculator follows that hierarchy exactly.
Protein first. Protein determines whether your surplus becomes muscle. The research consensus lands at 1.6 to 2.2 grams per kilogram per day; we set your number inside that range by training experience, because muscle protein synthesis responds differently at each stage. Protein is the one number to treat as a daily target.
Fat second. Set at 25% of total calories: enough to support hormones and add easy calorie density (a tablespoon of olive oil is 120 nearly effortless calories), without crowding out training fuel.
Carbs last, and largest. Whatever calories remain go to carbs. That is a feature: carbs fuel your lifting, refill glycogen, and are the easiest macro to eat more of when the surplus feels hard. A lean-bulk variant is the same math with a smaller calorie target; set your rate in the surplus calculator and this split adjusts automatically.
Need the calorie target first? Use the calorie surplus calculator, then come back.
Frequently asked questions
How much protein do I need to bulk?
The evidence-backed range is 1.6 to 2.2 grams per kilogram of body weight daily, roughly 0.7 to 1 gram per pound. This calculator sets it by training experience: newer lifters sit at the lower end because their bodies respond strongly to any stimulus, while advanced lifters benefit from the top of the range.
Why is fat set at 25% of calories?
Fat intakes around 20 to 30% of calories support hormone production and make high-calorie eating easier, since fat is the most calorie-dense macro. Going much lower makes a surplus hard to eat; much higher starts crowding out carbs that fuel training.
Do carbs matter for gaining weight?
Yes, carbs are the flexible workhorse of a bulk. After protein and fat are set, carbs fill the remaining calories, fuel your lifting sessions, and support recovery. For most hardgainers, under-eating carbs is where the surplus quietly fails.
Do I have to hit these numbers exactly every day?
No. Protein is the target worth hitting daily; carbs and fat can trade against each other freely as long as total calories land. Consistency across the week beats precision on any single day.
Sources
- Morton RW et al., A systematic review of protein supplementation on resistance training outcomes, Br J Sports Med (2018): The 1.6-2.2 g/kg protein range used for the protein target.
- Iraki J et al., Nutrition recommendations for bodybuilders in the off-season, Sports (2019): Off-season macro splits: protein anchored, fat at 20-30% of calories, carbs filling the remainder.
- Helms ER et al., Evidence-based recommendations for natural bodybuilding contest preparation, JISSN (2014): Macro hierarchy (calories first, then protein, then fat/carb flexibility).