Macro Split Calculator
A calorie target tells you how much to eat; a macro split tells you what to eat. This calculator converts your daily calories into grams of protein, carbohydrate and fat, which is the level of detail that decides whether you keep muscle while losing fat.
Inputs
Result
165g P · 220g C · 73g F
Visual breakdown
How the macro split calculator works
Energy per gram: protein 4 kcal, carbohydrate 4 kcal, fat 9 kcal. Grams = calories allocated to that macro ÷ its energy density.
A reliable approach is to set protein first at 1.6–2.2 g per kg of bodyweight, then fat at a minimum of 0.6–0.8 g per kg for hormonal health, then fill the remainder with carbohydrate.
Percentage splits such as 40/30/30 are convenient but can leave protein too low at small calorie targets, which is exactly when protein matters most.
Worked example: 2,100 kcal for a 75 kg lifter
- Protein at 2.0 g/kg: 150 g = 600 kcal.
- Fat at 0.8 g/kg: 60 g = 540 kcal.
- Remaining for carbohydrate: 2,100 − 1,140 = 960 kcal = 240 g.
- Split: 150 g protein, 240 g carbs, 60 g fat — roughly 29/46/26 by calories.
- A generic 40/30/30 split at the same calories would give only 158 g carbs and 210 g protein-equivalent mismatch, over-fatting the diet at 70 g.
Common mistakes to avoid
Setting percentages before protein
Percentage-first splits scale protein down as calories fall. Anchor protein in grams per kilogram and let the percentages land where they land.
Cutting fat too low
Below roughly 0.5 g per kg, hormone production and fat-soluble vitamin absorption suffer. Fat is not the enemy of a deficit.
Ignoring fibre
Fibre is a subset of carbohydrate and drives satiety. Aim for 25–35 g a day; a technically perfect macro split of low-fibre food will leave you hungry.
Frequently asked questions
What is the best macro split?
The one you can follow that hits adequate protein. Protein 1.6–2.2 g/kg, fat at least 0.6 g/kg, carbohydrate filling the rest works for most goals.
Do macros matter more than calories?
Calories determine weight change; macros determine what that change is made of and how well you train and recover.
How much protein is too much?
Intakes up to about 3 g/kg are safe for healthy kidneys, though benefits plateau above roughly 2.2 g/kg.
Should carbs be lower for fat loss?
Not necessarily. Low-carb diets work through appetite reduction, not metabolic advantage. Choose based on adherence and training demands.
Do I need to hit macros exactly?
Within about 5–10 g of protein and fat, and within 20 g of carbohydrate, is more than precise enough.
Learn more
Set protein first: the macro order that actually works
Percentage splits quietly starve you of protein exactly when you need it most. Here is the better sequence.
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