What next?
Macros come from a calorie target. These are the checks either side of them.
What your result means
Each macronutrient carries a fixed energy value — protein and carbohydrate about 4 kcal per gram, fat about 9. The split converts percentages of your calorie target into grams you can actually weigh and log. Protein per kg is the most useful sanity check: most guidance for active adults lands between 1.2 and 2.0 g per kg of body weight.
Why this one is different
Protein leads the readout, with carbohydrate and fat beneath it and a Split used row naming the ratio those grams came from — so every figure is traceable to a choice you made rather than to an unstated default. A protein-per-kilogram row sits alongside the gram total, which is the unit sports nutrition guidance is written in.
Get protein and total calories right; the rest is preference
Evidence for one specific carb-to-fat ratio being superior is thin once protein and calories are matched. What consistently shows up in research is adequate protein for preserving muscle in a deficit, and a total intake you can actually sustain.
So set protein first, then divide what remains between carbohydrate and fat according to what makes your meals enjoyable and your training feel good. Adherence beats optimisation.
How it works
The calculator takes your calorie target, applies the chosen percentage split, then divides each share by that macronutrient’s energy density to get grams. Fat is derived as the remainder in custom mode so the three always total 100%.
How to use this calculator
- Enter your daily calorie target — use the TDEE calculator if you do not have one.
- Choose a split, or select Custom and set protein and carbohydrate with the sliders.
- Add your body weight to check protein per kilogram.
- Log the gram targets rather than the percentages — grams are what you can measure.
Formula
Energy density: protein 4 kcal/g, carbohydrate 4 kcal/g, fat 9 kcal/g. Alcohol, at 7 kcal/g, is not modelled.
Example calculation
A 2,400 kcal target on a balanced 30/40/30 split:
Carbohydrate = 2,400 × 0.40 ÷ 4 = 240 g
Fat = 2,400 × 0.30 ÷ 9 = 80 g
Frequently asked questions
How much protein do I actually need?＋
Sedentary adults need around 0.8 g per kg. Active adults and anyone in a calorie deficit generally do better between 1.2 and 2.0 g per kg, with the upper end favoured when training hard while losing weight.
Is a low-carb split better for fat loss?＋
Not inherently. Controlled trials matching calories and protein find little difference in fat loss between low-carb and higher-carb diets. Choose the one you can stick to and that supports your training.
Do I need to hit the numbers exactly?＋
No. Landing within about 10 g of protein and roughly on calories is more than precise enough. Chasing exact gram counts adds stress without adding results.
How do I convert grams to calories?＋
Protein and carbohydrate supply about 4 kcal per gram, fat about 9 kcal per gram, and alcohol about 7. Multiplying your gram targets by those figures should return roughly your calorie target.
Is there a minimum fat intake?＋
Most guidance keeps fat at or above roughly 20 percent of calories, because dietary fat carries fat-soluble vitamins and supports hormone production. Very low-fat diets are hard to sustain for that reason.
Should I change macros on rest days?＋
It is not necessary for most people. Keeping intake consistent is simpler to follow, and weekly totals are what drive the outcome.
What about fibre?＋
Fibre is part of your carbohydrate total, and most adults fall short of the 30 g a day commonly recommended. Aim for that alongside the macro split rather than treating it separately.
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Assumptions & limitations
Every figure here comes from a simplified model. Keep these limits in mind when reading your result:
- Uses standard Atwater energy values, which are averages across food types.
- Does not account for alcohol, fibre adjustments or individual digestive differences.
- Not suitable for people with kidney disease, diabetes or other conditions requiring managed intake without medical advice.
- Assumes the calorie target you enter is appropriate for you.