Free tool

Macro calculator

Give it a calorie target and it returns grams of protein, carbs and fat. Pick a preset or drag the split yourself — the maths is the same one the app uses.

Don't know it? Get it from the TDEE calculator first, then subtract for a deficit or add for a surplus.

How the numbers are worked out

Each macro carries a known amount of energy — this is the Atwater system, and it is what every tracker runs on:

  • Protein — 4 kcal per gram
  • Carbohydrate — 4 kcal per gram
  • Fat — 9 kcal per gram

So a percentage split is just the calorie target divided up and converted. 30% protein of 2,200 kcal is 660 kcal, which at 4 kcal per gram is 165 g.

Two floors are applied afterwards, because a percentage that looks reasonable can produce a number that is not. Protein is held at a minimum of roughly 1.6 g per kg of body weight where your calories allow it, and fat is held at a minimum of about 20% of calories — going far below that for long stretches is not a trade most people should make. If a floor moved your numbers, the calculator says so underneath rather than silently overriding you.

The protein floor this calculator applies is set from the meta-analytic dose-response: benefit plateaus near 1.62 g per kg of bodyweight, with the confidence interval reaching about 2.2 g/kg.1 If a percentage split would put you below that, we raise protein and say so rather than letting a tidy-looking percentage produce a number that is too low.

Which split should you pick?

Balanced suits most people most of the time. Higher protein is worth it in a deficit, when protein does the most work holding onto muscle. Lower carb is a preference, not a fat-loss advantage — the research is clear that when calories and protein are matched, the split does not change fat loss. Endurance shifts calories toward carbs if you are training long. Keto is a specific tool with real trade-offs; if you are using it, you probably already know why.

The honest summary: get the calories roughly right, get protein high enough, and stop optimising the rest.

The problem with any fixed number

This calculator hands you a target based on the calorie figure you typed in. That figure came from an equation, and equations describe averages — individuals routinely sit a few hundred kcal either side. Worse, the number ages: expenditure drifts as you lose weight, as activity changes, as adherence changes.

Which is why the number worth having is one measured from your own logging and your own weight trend, corrected weekly. That is what adaptive TDEE means, and it is what MacroPair does with the numbers this page gives you.

References

Every figure on this page traces to one of these. We checked each against the primary source rather than citing from memory; follow the links and hold us to them.

  1. Morton RW, Murphy KT, McKellar SR, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6):376–384. PMID 28698222 Pooled 49 studies (1,863 participants). Gains plateaued near 1.62 g protein per kg bodyweight per day, with the confidence interval reaching about 2.2 g/kg.
  2. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. (1990). A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition, 51(2):241–247. PMID 2305711 Derived from 498 healthy adults aged 19–78. This is the equation behind our TDEE calculator: 10×kg + 6.25×cm − 5×age, +5 for men and −161 for women.
  3. Frankenfield D, Roth-Yousey L, Compher C. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association, 105(5):775–789. PMID 15883556 Mifflin-St Jeor was the most reliable equation reviewed — and still landed within 10% of measured resting metabolic rate for only about 80% of people. Roughly one person in five sits further out than that.

Common questions

Do I need to hit my macros exactly?
No. Being within roughly 5–10 g on protein and reasonably close on calories is enough for the result you are after. Precision beyond that mostly costs you sanity without buying anything.
What if I only track calories and protein?
That is a perfectly good way to do this, and for a lot of people it is the version they will actually keep doing. Carbs and fat can trade freely as long as fat does not sit very low for months.
Does fiber count toward carbs?
On the numbers this calculator uses, yes — fiber is part of the carbohydrate total, which is how US nutrition labels report it. Some regions and some apps subtract it. Either convention is fine as long as you do not mix them.
Should my partner use the same split?
The split can be shared. The calorie total almost certainly should not — see the guide on tracking as a couple.
Do the numbers change on training days?
They can. A common approach is to keep protein and fat steady and put the extra calories into carbs on days you train. MacroPair does this automatically once it knows your training days.

General wellness information, not medical advice — see our health disclaimer. Talk to a clinician before making significant dietary changes.