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Macro Calculator

Turn your daily calorie target into grams of protein, carbs and fat for a balanced, low-carb, high-protein, keto or custom diet, with amounts per meal.

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Goal and diet

Results are estimates, not medical or dietary advice.

How to use the macro calculator

Enter your age, sex, weight, height and usual activity level, then choose a goal and a diet split. The calculator first estimates your daily calorie target and then divides it into the three macronutrients. Pick 3, 4 or 5 meals to see roughly how much of each macro to put on every plate. If you know your body fat percentage, you can switch the energy formula to Katch-McArdle.

The diet splits

Each split is written as protein / carbs / fat, as a percentage of calories:

  • Balanced 30 / 40 / 30: a middle-of-the-road option that suits most people.
  • Low carb 40 / 20 / 40: fewer starches and sugars, more protein and fat.
  • High protein 40 / 30 / 30: popular when trying to keep or build muscle.
  • Keto 25 / 5 / 70: very low carb, so the body relies mostly on fat for fuel.
  • Custom: enter your own three percentages. They must add up to 100.

How the numbers are worked out

  1. Daily energy use is estimated with Mifflin-St Jeor (or Katch-McArdle) and multiplied by your activity factor.
  2. The goal adjusts it: about 500 kcal less per day to lose 1 lb a week (550 kcal for 0.5 kg), or about 250 kcal more to gain 0.5 lb a week (275 kcal for 0.25 kg). This uses the common 3,500 kcal per lb (7,700 kcal per kg) rule.
  3. Each macro gets its share of the calories and is converted to grams: protein and carbs have about 4 kcal per gram, fat about 9 kcal per gram.
  4. Grams per meal are the daily grams divided by the number of meals, rounded to whole grams.

Worked example

A 30-year-old man who weighs 80 kg, is 180 cm tall and exercises moderately needs about 2,759 kcal a day to maintain his weight. With the balanced split:

  • Protein: 30% of 2,759 = 828 kcal ÷ 4 ≈ 207 g
  • Carbs: 40% = 1,104 kcal ÷ 4 ≈ 276 g
  • Fat: 30% = 828 kcal ÷ 9 ≈ 92 g

Over 4 meals that is about 52 g protein, 69 g carbs and 23 g fat each. If he chose keto and wanted to lose 0.5 kg a week instead, his target would drop to 2,209 kcal: about 138 g protein, 28 g carbs and 172 g fat.

Good to know

  • Macro targets are a guide for planning, not exact rules. Hitting your calories and protein consistently matters more than matching every gram.
  • Fibre counts as a carb here. Food labels and apps may treat it differently.
  • Very low-carb and very low-calorie diets are not right for everyone. A target below 1,200 kcal (women) or 1,500 kcal (men) is marked with a warning.
  • All results are estimates and not medical or dietary advice. Talk to a doctor or registered dietitian if you have a health condition, are pregnant or plan a big change.

Frequently asked questions

What are macros?

Macros, short for macronutrients, are the three nutrients that provide most of the energy in food: protein, carbohydrates and fat. Tracking them in grams gives you more detail than counting calories alone.

Why is fat 9 kcal per gram but protein and carbs only 4?

Fat is a more concentrated energy source. These standard values, often called Atwater factors, are used on most nutrition labels, so a gram of fat supplies a little more than twice the energy of a gram of protein or carbohydrate.

Which diet split is best?

There is no single best split. Studies suggest that total calories and enough protein matter most for weight change, while the ratio of carbs to fat is largely a matter of preference and what you can stick with. Start with balanced if you are unsure.

Can I enter my own percentages?

Yes. Choose Custom and enter the protein, carb and fat percentages. They must add up to exactly 100, and decimals such as 33.3 / 33.3 / 33.4 are accepted.