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Free Macro Calculator

Calculate your perfect macros

Get personalised daily targets for protein, carbs, fats, and calories using the scientifically-backed Mifflin-St Jeor equation.

How the Macro Calculator Works

This calculator uses the Mifflin-St Jeor equation, one of the most accurate methods for estimating your Basal Metabolic Rate (BMR). Your BMR is the number of calories your body burns at complete rest.

The Mifflin-St Jeor Equation

Males: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5

Females: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

We then multiply your BMR by an activity factor to get your Total Daily Energy Expenditure (TDEE), and adjust based on your goal:

  • Lose weight: TDEE − 500 kcal (safe deficit for ~0.5kg/week loss)
  • Maintain: TDEE as-is
  • Gain muscle: TDEE + 300 kcal (lean surplus)

How Macros Are Split

We calculate your macro targets using evidence-based ratios:

  • Protein: 2g per kg bodyweight (essential for muscle retention)
  • Fats: 25% of total calories (hormonal health, absorption)
  • Carbs: Remaining calories (energy for training and life)

Once you know your targets, use Chowdown to track them for free — just snap photos of your food and we'll handle the rest.