Bulking Macro Calculator

Carbohydrate is the fuel your muscles draw on during training, stored as glycogen and topped up by what you eat. A bulking split gives carbohydrate the largest share for that reason, so more of each day’s calories go toward refilling that fuel. In gram terms the split is just arithmetic: you decide the percentage each macro takes, then divide those calories by the energy each gram carries — 4 calories per gram for protein and carbohydrate, 9 for fat. Because carbohydrate holds 4 calories a gram, a 50% share turns into a large number of grams; the fat share, at 9 calories a gram, converts into far fewer. Set the split with the Macro Calculator, then check the protein grams against your body weight with the Protein Intake Calculator.

Take a 2,800-calorie day on the 30/50/20 split as a worked example. Protein takes 30%, which is 840 calories, and at 4 calories per gram that is 210 grams. Carbohydrate takes 50%, or 1,400 calories, again at 4 calories per gram — 350 grams. Fat takes the last 20%, 560 calories, but fat carries 9 calories in every gram, so it comes to about 62 grams. Add the calories back — 840 plus 1,400 plus 560 — and you return to 2,800, which is the check that the split is complete. Change the calorie total and each gram figure scales with it, while the three shares always add to 100%.

A bulk is defined by its surplus — how far above maintenance you eat — and that is an upstream calorie decision this page does not make. This tool only splits whatever total you give it into grams; it does not work out how large the surplus should be, because that depends on the energy your own body burns. Find that figure first with the TDEE Calculator, add your surplus to it, then bring the total back here to split. These figures are general estimates for healthy adults, not medical advice.