Free Macro Calculator - Calculate Protein, Carbs & Fat Targets
Calculate daily macronutrient targets based on body weight and fitness goals for optimal nutrition.
Formula & Methodology
This calculator estimates your Basal Metabolic Rate using the Mifflin-St Jeor equation, adjusts for activity level, and then divides your target calories into specific gram amounts for protein, fats, and carbohydrates based on standard nutritional guidelines.
- BMR (Mifflin-St Jeor) = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
- TDEE = BMR × Activity Multiplier
- Target Calories = TDEE × Goal Adjustment (e.g., 0.85 for weight loss)
- Protein = Weight in lbs × Target g/lb
- Fat = (Target Calories × 25%) / 9
- Carbs = (Target Calories - Protein Calories - Fat Calories) / 4
Worked Example
Using the Macronutrient Calculator: apply the formula above to your input values. For instance, BMR (Mifflin-St Jeor) = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5, then TDEE = BMR × Activity Multiplier. The tool performs each step instantly and shows the result.
Frequently Asked Questions
What are macronutrients?
Protein, carbohydrates and fat — the three nutrients your body needs in large amounts for energy, muscle repair and hormone function.
How should I split my macros?
A common starting point is higher protein for muscle retention, moderate fat, and the rest from carbs, then adjust based on your energy and results.
Do macro needs change with my goal?
Yes. Fat loss usually raises the protein share and lowers calories, while muscle gain increases carbs and total energy to fuel training.