OmniTools

Macro Calculator

Split a daily calorie target into grams of carbohydrate, protein and fat.

Basis: Grams = daily calories × share ÷ Atwater factor (4 kcal/g for carbohydrate and protein, 9 kcal/g for fat), the general Atwater factors in the FAO food energy report; the splits were checked against the National Academies’ AMDR·2026-11-02 verified·Not reviewed by a medical professional·Editorial policy

Before you rely on this

The three splits are starting points, not prescriptions. Against the adult ranges set by the US National Academies (carbohydrate 45–65%, protein 10–35%, fat 20–35%), the carbohydrate share of “Balanced” and “Lower carb” sits below the range. With diabetes or kidney disease, or during pregnancy, agree a split with a clinician first. The grams are only as good as the daily calorie figure you enter.

Tool Overview & Key Purpose

Splits a daily calorie target into carbohydrate, protein and fat, and tells you how many grams of each that is. It is for the step after you know your calorie target — turning a number of calories into something you can actually plan meals around.

Step-by-Step Usage Instructions

1STEP 1

Enter your daily calorie target. If you do not have one, work it out first with the BMR & TDEE calculator.

2STEP 2

Pick a split — Balanced 40·30·30, High protein 35·40·25, Lower carb 25·40·35, or Custom.

3STEP 3

For a custom split, make the three percentages add up to 100; otherwise a warning replaces the grams.

4STEP 4

Read the daily grams and the per-meal figure for three meals, and copy the result if you want to keep it.

Real-World Scenarios & Practical Cases

3 Practical CasesScenario #1

2,200 kcal a day, Balanced

Carbohydrate at 40% is 880 kcal, or 220 g; protein at 30% is 660 kcal, or 165 g; fat at 30% is also 660 kcal, but at 9 kcal per gram that is 73 g. Over three meals that is about 73 g, 55 g and 24 g each.

165 g of protein is 2.4 g/kg for a 70 kg person — on the high side. If you train lightly, even the Balanced split is generous on protein.Scenario #2

1,700 kcal while cutting, High protein

A 35·40·25 split gives 149 g carbohydrate, 170 g protein and 47 g fat. Raising the protein share while eating less is the usual advice for limiting muscle loss.

Fewer calories means fewer grams at the same percentage, so check protein against grams per kilogram of body weight as well.Scenario #3

Custom split for an endurance block

During a week of long runs, raising carbohydrate to 55·20·25 at 2,800 kcal gives 385 g carbohydrate, 140 g protein and 78 g fat.

The split does not have to stay fixed — many people change it day by day with training load.How grams are worked out

Calories for a nutrient = daily calories × its share
Carbohydrate (g) = carbohydrate calories ÷ 4
Protein (g) = protein calories ÷ 4
Fat (g) = fat calories ÷ 9
4·4·9 are the general Atwater factors. Alcohol (7 kcal/g) and fibre are not counted separately.

Pro Tips & Key Considerations

The grams are grams of the nutrient, not of food. 100 g of chicken breast holds about 23 g of protein — do not mix the two up.The US National Academies’ adult ranges are carbohydrate 45–65%, protein 10–35% and fat 20–35%. This tool’s Lower carb split sits below that carbohydrate range.Hold one split for a week or two, watch weight and energy, then move in steps of 5% — that way you can tell what changed what.

Frequently Asked Questions (FAQ)

Sources & References

FAO — Calculation of the Energy Content of Foods: Energy Conversion Factors National Academies — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids