Macro Calculator

Turn your daily calories into grams of protein, carbs and fat. Protein comes first and is based on your bodyweight; fat and carbs share the rest.

Your details

kcal/day
kg

Don't know your calories? Use the Calorie Calculator for a target to lose, keep or gain weight.

Your results

Enter your daily calories and bodyweight.

How to use it

  1. Enter your daily calories. Don't have a number? Get one from the Calorie Calculator.
  2. Enter your bodyweight.
  3. Pick a protein level and a fat share. The defaults suit most lifters.
  4. Read your grams per day. Carbs fill whatever calories are left.

How it's calculated

The calculator sets the three macros in a fixed order:

  1. Protein = your choice in g per kg × bodyweight. The options run from 1.6 to 2.2 g/kg: a meta-analysis by Morton and colleagues (2018) found gains in muscle level off around 1.6 g/kg, with 2.2 g/kg as the upper end of their estimate.
  2. Fat = your chosen share of calories (20–35%, the adult range from the Institute of Medicine), divided by 9 kcal per gram.
  3. Carbs = the calories left over, divided by 4 kcal per gram.

Example: 2,500 kcal at 80 kg, 2.0 g/kg protein and 25% fat gives 160 g protein (640 kcal), 69 g fat (625 kcal) and 309 g carbs (1,235 kcal).

Energy per gram uses the standard factors from food labels: 4 kcal for protein and carbs, 9 kcal for fat.

Checks. If protein and fat alone take up all your calories, the calculator asks you to lower one of them. If carbs come out under 3 g per kg, it warns you: a review for lifters (Iraki et al., 2019) suggests at least 3 to 5 g/kg.

Sources

  1. Morton, R. W., Murphy, K. T., McKellar, S. R., Schoenfeld, B. J., Henselmans, M., Helms, E., Aragon, A. A., Devries, M. C., Banfield, L., Krieger, J. W., & Phillips, S. M. (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.
  2. Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: National Academies Press. Acceptable macronutrient distribution ranges.
  3. Iraki, J., Fitschen, P., Espinar, S., & Helms, E. (2019). Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports, 7(7), 154.

Questions

What's the best macro split?

There isn't one best split. Protein matters most for building and keeping muscle; the balance of carbs and fat after that is largely personal preference. Pick a split you can stick to.

How much protein do I need?

For lifters, about 1.6 g per kg of bodyweight a day gets most of the benefit for muscle growth, and up to 2.2 g/kg can help a little more, especially when dieting. The Protein Calculator covers more goals.

Why is fat set as a share of calories?

Health guidelines (Institute of Medicine) give an adult range of 20 to 35% of calories from fat. Going much lower makes it hard to get enough essential fats.

Why does it warn about low carbs?

Carbs fuel hard training. A 2019 review for lifters suggests at least 3 to 5 g per kg of bodyweight. If yours come out lower, lowering your fat share frees up calories for carbs.

Updated November 9, 2026.