Macro Calculator

Dial in your daily protein, carbs and fat based on your body, activity level and goal.

Sex
yrs
Height
cm
Weight
kg

What is a macro calculator?

This macro calculator turns your daily calorie target into gram targets for the three macronutrients — protein, carbohydrates and fat — matched to whether you're cutting, maintaining or building muscle. Counting macros instead of just calories is how you make sure the weight you lose is fat and the weight you gain is muscle.

How it works

Your calories are calculated from the Mifflin–St Jeor equation and your activity level, then adjusted for your goal: a 20% deficit for fat loss, maintenance calories, or a 10% surplus for muscle gain. Macros are then set in this order:

  • Protein first: 1.8–2.2 g per kg of body weight depending on goal — higher while cutting to protect muscle. A 2018 meta-analysis of 49 trials found benefits of protein intake for muscle growth plateau around 1.6–2.2 g/kg.
  • Fat second: 25% of total calories, within the 20–35% range recommended by the Institute of Medicine and enough to support hormone production.
  • Carbs last: whatever calories remain — your training fuel.

Frequently asked questions

Do I have to hit my macros exactly?

No. Within ±5–10 g of each target is effectively perfect. Prioritise the protein number and total calories; carbs and fat can flex against each other day to day.

Should I change macros on rest days?

It's optional. Total weekly intake matters far more. Some people shift carbs toward training days ("carb cycling"), but the evidence advantage is small — do it only if it suits your routine.

References

  1. Morton RW, Murphy KT, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. Br J Sports Med. 2018;52(6):376–384.
  2. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005.
  3. Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990;51(2):241–247.

Related

These results are estimates for healthy adults and are not medical advice. Consult a health professional before making major changes to your diet or training.

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