The formula
How it works
Turn a daily calorie target into grams of carbohydrate, protein and fat. Pick a diet split — from balanced to keto — and the calculator divides your calories into the three macronutrients.
FAQ
How many calories are in each macro?
Carbohydrate and protein each provide 4 calories per gram, while fat provides 9. That is why a high-fat diet has fewer grams for the same calories, and why fat is so energy-dense.
Which split should I choose?
A balanced 40/30/30 works for most people. Higher protein helps preserve muscle when losing weight, low-carb and keto shift energy to fat, and high-carb suits endurance athletes. The best split is the one you can stick to.
How much protein do I actually need?
Many active adults aim for roughly 1.6–2.2 g of protein per kilogram of bodyweight; the percentage split here converts a chosen protein share of total calories into grams, so check the gram figure against your bodyweight target too.
Why does keto have so little carbohydrate?
Keto restricts carbs to a small share of calories so the body shifts to burning fat for fuel and producing ketones, which is the metabolic state the diet is named after.
Do these grams include fiber?
No — this calculator splits total carbohydrate by calorie share, and food labels usually count fiber within total carbs, so net (digestible) carbs will be a little lower than the gram figure shown.
Should my macros change on rest days versus training days?
Many people do lower carbs slightly on rest days and raise them on hard training days, while keeping protein fairly constant, though a fixed daily split like this one is simpler to follow.
What if I want to gain or lose weight, not just hit a split?
The macro split only decides how your calories are divided — whether you gain, lose or maintain weight depends on the total calorie number you enter, so adjust that first with a calorie or TDEE calculator.
About the macro calculator
This calculator breaks a daily calorie target down into grams of the three macronutrients: carbohydrate, protein and fat. Counting calories tells you how much to eat overall, but macros tell you what those calories should be made of — and that balance affects energy, muscle and how full you feel. By converting percentages into grams, this tool turns a diet plan into numbers you can actually track on a food label.
How to use it
Enter your daily calorie target — from a calorie or TDEE calculator — and choose a diet split. The calculator shows how many grams of carbs, protein and fat that split works out to. For example, 2,000 calories on a balanced 40/30/30 plan gives about 200 g of carbs, 150 g of protein and 67 g of fat. Switch to low-carb or keto to see how the grams shift toward protein and fat.
The formula
Each macro’s grams come from its share of the calories divided by its energy density: . Carbohydrate and protein are 4 calories per gram, and fat is 9. So 30% of 2,000 calories as protein is 600 calories, which at 4 per gram is 150 g; the same 30% as fat is 600 calories at 9 per gram, only about 67 g.
Where it is used
Anyone tracking their diet closely uses macros, from bodybuilders fine-tuning muscle gain to people managing blood sugar with lower carbs. Coaches prescribe macro targets alongside calories, and fitness apps let you log food against them. Because the same calorie total can be built from very different macro splits, this breakdown is what turns a calorie goal into a practical daily eating plan.