How macro targets are worked out
The calculator first estimates your maintenance calories from your sex, age, height, weight and activity level, then applies your goal: a 500 kcal deficit for weight loss or a modest 250 kcal surplus for muscle gain. Your chosen split divides those calories between the three macros, converting to grams at 4 kcal per gram for protein and carbs and 9 kcal per gram for fat.
Percentages are a starting point, not a law. Many coaches prefer to set protein first in grams per kilogram of body weight, then let carbs and fat fill the remaining calories according to preference. If that appeals, our protein calculator gives you the precise protein figure to build around.
Choosing a split you can live with
The best macro split is the one you can follow on a normal Tuesday, not just a perfect week. If you love bread and rice, a lower-carb split will feel like a punishment and you will abandon it. If heavy training days leave you flat, more carbohydrate usually helps. Treat the presets as sensible defaults and adjust after a couple of weeks of real data.
