Macros — short for macronutrients — are the three nutrients that supply energy: protein and carbohydrate at about 4 kcal per gram and fat at about 9 kcal per gram. Your macro split is how your daily calories are divided between them.

How do I calculate my macros?

Estimate your daily calorie target first (BMR via Mifflin–St Jeor × an activity factor, then adjusted for your goal). Set protein from bodyweight (around 1.8–2.0 g per kg), set fat as a share of calories (about 27–30%), and fill the remaining calories with carbohydrate. This calculator does all of that for you.

What's the best macro ratio for fat loss or muscle gain?

There's no single perfect ratio. For fat loss, keep protein high (around 2.0 g/kg) to protect muscle in a calorie deficit; for muscle gain, eat in a slight surplus with around 1.8 g/kg protein and enough carbs to fuel training. Fat usually sits near 25–30% of calories either way, with carbs as the remainder.

Should I count macros or just calories?

Calories drive weight change, so tracking calories alone works for many people. Counting macros adds control over body composition and performance — hitting a protein target in particular helps preserve muscle when cutting and supports growth when gaining.

How accurate is this macro calculator?

It's a solid starting estimate. The calorie figure relies on the Mifflin–St Jeor equation and an activity multiplier, both of which vary by individual. Use the numbers for a week or two, track your weight trend, and adjust calories up or down as needed.

Macro Calculator

This macro calculator splits your daily calories into protein, carbohydrate and fat grams for your goal — cut, maintain or gain — using the Mifflin–St Jeor energy estimate. Set your details and read your daily targets straight off the dial.

How it works

The calculator builds your split in three steps. First it estimates your daily calorie target: basal metabolic rate (BMR) from the Mifflin–St Jeor equation, times an activity factor to get total daily energy expenditure (TDEE), then adjusted for your goal (a 20% deficit to cut, maintenance to hold, a 12% surplus to gain).

Then it allocates the macros:

Protein= bodyweight in kg × the goal's protein factor (2.0 g/kg cutting, 1.8 g/kg otherwise).
Fat = a fixed share of the calorie target (27–30% depending on goal), divided by 9 kcal per gram.
Carbohydrate = the remaining calories after protein and fat, divided by 4 kcal per gram.

Protein and carbs supply about 4 kcal per gram and fat about 9, so the three gram totals always add back up to your calorie target.

Worked example

Take an 80 kg, 180 cm, 30-year-old man who trains moderately and wants to maintain. His BMR is 1,780 kcal; at a 1.55 activity factor that's a TDEE and target of about 2,759 kcal. Protein is 1.8 g/kg × 80 = 144 g (576 kcal). Fat is 30% of 2,759 ÷ 9 ≈ 92 g (828 kcal). That leaves 2,759 − 576 − 828 = 1,355 kcal of carbohydrate, or about 339 g.

Macro strategy by goal

Each goal shifts the calorie target and protein floor; fat stays a share of calories and carbs take the remainder:

Goal	Calories	Protein	Fat	Carbs
Cut	0.80 × TDEE	2.0 g/kg	27% of kcal	Remainder
Maintain	1.00 × TDEE	1.8 g/kg	30% of kcal	Remainder
Gain	1.12 × TDEE	1.8 g/kg	27% of kcal	Remainder

Higher protein when cutting protects lean mass in a deficit; carbs expand on a gain to fuel harder training.

Frequently asked questions

What are macros?: Macros — short for macronutrients — are the three nutrients that supply energy: protein and carbohydrate at about 4 kcal per gram and fat at about 9 kcal per gram. Your macro split is how your daily calories are divided between them.
How do I calculate my macros?: Estimate your daily calorie target first (BMR via Mifflin–St Jeor × an activity factor, then adjusted for your goal). Set protein from bodyweight (around 1.8–2.0 g per kg), set fat as a share of calories (about 27–30%), and fill the remaining calories with carbohydrate. This calculator does all of that for you.
What's the best macro ratio for fat loss or muscle gain?: There's no single perfect ratio. For fat loss, keep protein high (around 2.0 g/kg) to protect muscle in a calorie deficit; for muscle gain, eat in a slight surplus with around 1.8 g/kg protein and enough carbs to fuel training. Fat usually sits near 25–30% of calories either way, with carbs as the remainder.
Should I count macros or just calories?: Calories drive weight change, so tracking calories alone works for many people. Counting macros adds control over body composition and performance — hitting a protein target in particular helps preserve muscle when cutting and supports growth when gaining.
How accurate is this macro calculator?: It's a solid starting estimate. The calorie figure relies on the Mifflin–St Jeor equation and an activity multiplier, both of which vary by individual. Use the numbers for a week or two, track your weight trend, and adjust calories up or down as needed.

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Disclaimer. This macro calculator gives an estimate for general fitness planning, not medical or nutritional advice. Energy needs and ideal macro splits vary between individuals — track your results and adjust, and consult a qualified professional for personalised guidance.