Macro Calculator

Stop guessing about your plate. Whether you want to lose fat, maintain your current weight, or build lean muscle, macronutrients — protein, carbohydrates, and fat — are the levers that control body composition. This free macro calculator turns your weight, body-fat percentage, activity level, and goal into precise daily targets for each macronutrient.

Macronutrients are the three energy-providing nutrients your body needs in large amounts. Protein and carbohydrates each provide about 4 calories per gram, while fat provides about 9 calories per gram. Protein repairs tissue and supports muscle; carbohydrates fuel workouts and brain function; fats regulate hormones and help absorb fat-soluble vitamins A, D, E, and K.

How to use the calculator

Enter your weight in kilograms and your estimated body-fat percentage. Choose your primary goal — lose fat, maintain, or build muscle — and pick the activity level that best matches your week. The calculator uses the Katch-McArdle formula to estimate your basal metabolic rate from lean body mass, multiplies by an activity factor for your total daily energy expenditure (TDEE), then adjusts calories based on your goal.

Worked example

Imagine a 70 kg person with 20% body fat. Their lean body mass is 56 kg. Using Katch-McArdle, BMR ≈ 370 + 21.6 × 56 ≈ 1,580 kcal. With light activity (1.375), TDEE ≈ 2,173 kcal. For fat loss at 80% of TDEE, the target is about 1,738 kcal. Protein is set at 2.4 g per kg of lean mass ≈ 134 g (538 kcal). Fat at 25% of calories ≈ 48 g (434 kcal). The remaining calories fill carbohydrates: ≈ 192 g (766 kcal).

Common use cases

• Fat loss with muscle preservation — high protein, moderate carbs, calorie deficit.
• Maintenance — balanced split aligned with TDEE after a diet.
• Lean bulking — moderate surplus with carbs fueling resistance training.
• IIFYM / flexible dieting — hit daily macro targets without rigid meal plans.
• Keto planning — very low carbs, high fat, moderate protein.

Tips for success

Weigh food with a digital scale for the first few weeks so you learn real portions. Prioritize protein at every meal. Aim for 80-90% of your intake from whole foods and use the remaining flexibility for foods you enjoy. Adjust your macros every 4-6 weeks based on the scale, progress photos, strength levels, and energy. And remember — weekly averages matter more than daily perfection.

For a broader view of your total daily energy expenditure, pair this tool with our Calorie Calculator or check your protein target with the Protein Calculator.