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Macro calculator: calories and protein for your goal

Pick a method, enter your details and see where every number comes from. No sign-up.

See the differences

Age · Weight (lb) · Height (ft, in)

What each method is

All three estimate the same thing, your resting energy (what your body burns without moving), from different inputs. The result is then multiplied by your activity and adjusted for your goal.

Mifflin-St Jeor

Published in 1990 by Mifflin, St Jeor and colleagues.

What it uses
Weight, height, age and sex.
Formula
Male: 10 × kg + 6.25 × cm − 5 × age + 5 · Female: 10 × kg + 6.25 × cm − 5 × age − 161
When to pick it
The default choice: the most widely used today and the one dietitians usually recommend for the general population.
Keep in mind
It doesn’t tell muscle from fat, so for very muscular people it can come out low.

Harris-Benedict

A classic equation from 1919, revised in 1984 (the version this calculator uses).

What it uses
Weight, height, age and sex.
Formula
Male: 88.362 + 13.397 × kg + 4.799 × cm − 5.677 × age · Female: 447.593 + 9.247 × kg + 3.098 × cm − 4.330 × age
When to pick it
Handy to compare with other calculators or an old result, since it was the reference for decades.
Keep in mind
It comes from another era and tends to give a slightly higher value than Mifflin-St Jeor.

Katch-McArdle

Proposed by Katch and McArdle, based on lean body mass.

What it uses
Your lean mass, worked out from your weight and body fat percentage. It ignores age and sex.
Formula
370 + 21.6 × lean mass (kg)
When to pick it
A good fit if you train and know your body fat percentage: it suits people with a lot of muscle better.
Keep in mind
It’s only as reliable as your body fat estimate. If you don’t know it, use Mifflin-St Jeor.

Frequently asked questions

Which method is best?

Mifflin-St Jeor is the most widely used today and the one the app uses. Katch-McArdle is better if you know your body fat percentage, because it starts from your lean mass. Harris-Benedict is the classic formula and tends to give a slightly higher value. All three are estimates: treat the result as a starting point and adjust it as your weight evolves.

How are the macros split?

Protein is set per kilo of body weight: 2.2 g to lose fat, 2.0 g to build muscle or strength and 1.8 g to maintain (capped at 40 % of calories). Fat is 25 % of calories. The rest is carbs.

Why is there a 1,200 kcal floor?

Because going below that, or below your resting energy, isn’t something a calculator should decide. If you need a bigger deficit, talk to a health professional.

Is it the same as the app?

Yes. With the Mifflin-St Jeor method, this calculator and FierFit Gym use the same formula and the same adjustments, so the result matches.

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