Macro Split Calculator
Percentages of energy, not of weight.
Work out Macro Split. Percentages of energy, not of weight. Shows the working, not just the answer.
Grams per day
150P · 200C · 67F
Balanced · 2 g of protein per kg
The percentages are of energy, not of weight. Protein and carbohydrate carry 4 calories a gram and fat carries 9, which is why a 30% fat allowance is a much smaller weight of food than a 30% carbohydrate one — and why label reading trips people up. Protein is the macro with the most robust evidence behind it. Around 1.6 to 2.2 g per kilogram supports muscle retention in a deficit and muscle growth in a surplus, and going much above that has little further effect. Beyond protein, the split matters far less than total calories and adherence. Low-carbohydrate and low-fat approaches produce near-identical results in controlled trials at matched calories and protein — which means the best split is the one you will actually follow.
How the Macro Split Calculator works
Turns a calorie target and a split into grams of protein, carbohydrate and fat, with protein per kilogram of body weight alongside. Preset splits from balanced through low-carb and ketogenic, or set your own.
Also known as: how many grams of protein carbs and fat · iifym macro calculator · 40 30 30 macro split · keto macros calculator
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
What is the best macro split?
For most goals, the one you will follow. Controlled trials at matched calories and protein find low-carb and low-fat approaches produce near-identical results, so adherence decides the outcome rather than the ratio.
How much protein do I need?
Roughly 1.6 to 2.2 g per kilogram of body weight supports muscle retention in a deficit and growth in a surplus. Above that range the additional benefit is small enough to be hard to measure.
Why are 30% fat and 30% carbohydrate different amounts of food?
Because the percentages are of energy. Fat carries 9 calories a gram against 4 for protein and carbohydrate, so an equal percentage of calories is a much smaller weight of fat.
Does a custom split have to add to 100?
Yes. The three percentages divide a fixed calorie total between them, so anything other than 100% would either invent or discard energy.
Do macros matter more than calories?
No. Calories decide whether weight moves; macros influence what the weight is made of and how full you feel getting there. Protein is the macro with the clearest independent effect.
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