Macro calculator

Protein comes first, set per kilogram of body weight: 2.2 g/kg when losing, 1.8 g/kg at maintenance, and 2.0 g/kg when gaining. Protein is the macro with the clearest evidence behind it — it protects lean mass in a deficit and is the most filling of the three, which is exactly what you want when calories are limited.

Fat and carbohydrate then split the calories that remain. The default sends 55% of the leftover to carbohydrate when losing and 50% at maintenance or in a surplus, with fat taking the rest. That places total fat near 30% of calories on a cut — comfortably inside the 20–35% range that dietary guidelines recommend.

The first is a floor on fat at 20% of total calories. Because protein is prescribed per kilogram of body weight rather than as a share of calories, a heavier person on an aggressive deficit can end up with almost nothing left for fat once protein and carbs are allocated. Dietary fat is not optional — it carries essential fatty acids and fat-soluble vitamins and supports hormone production. When the split would push fat under the floor, calories shift back from carbohydrate, the flexible macro. Carbohydrate has no floor, so deliberately low-carb and keto-style splits still work.

The second applies above a BMI of 25, where protein is calculated from an adjusted body weight rather than your full weight: the weight at a BMI of 25 plus 40% of the excess. This is the standard clinical convention, and the reasoning is simple — lean mass does not increase one-for-one with body fat, so a flat gram-per-kilogram target over-prescribes protein for higher-BMI profiles and squeezes out the other macros for no benefit.

Protein is the one worth chasing — get within about 10 g of the target most days. Carbohydrate and fat are far more flexible: trading some fat for carbs on a training day, or the reverse on a rest day, makes little difference as long as calories and protein hold.

Nobody hits three targets exactly, and it is not required. Consistently landing close beats occasionally landing perfectly, and the people who succeed at this are the ones who kept logging, not the ones who hit 100% every day.