Macro calculator
Use this macro calculator to turn a calorie target into protein, carbohydrate, and fat grams.
It gives a practical starting point for meal planning, but it is still an estimate. Real needs change with age, sex, body size, training, and how your weight changes over time.
If you want to check the calorie side first, the BMI calculator can help you compare body size with weight and height. For general nutrition guidance, the NIH has basic information on healthy eating and weight management.
How it's calculated
Step 1: estimate calories
A common approach is to start with maintenance calories, then apply a goal: - Lose weight: subtract about 250 to 500 kcal/day - Maintain: use estimated maintenance calories - Gain weight: add about 250 to 500 kcal/day
If maintenance is estimated from body size and activity, the calculator may use a formula such as Mifflin-St Jeor for BMR: - Men: BMR = 10×weight(kg) + 6.25×height(cm) - 5×age + 5 - Women: BMR = 10×weight(kg) + 6.25×height(cm) - 5×age - 161
Then multiply BMR by an activity factor to get TDEE.
Step 2: split calories into macros
A common split is: - Protein: 4 kcal per gram - Carbs: 4 kcal per gram - Fat: 9 kcal per gram
Example using a 2,000 kcal target with 30% protein, 40% carbs, and 30% fat: - Protein calories = 2,000 × 0.30 = 600 kcal → 600 ÷ 4 = 150 g - Carbs calories = 2,000 × 0.40 = 800 kcal → 800 ÷ 4 = 200 g - Fat calories = 2,000 × 0.30 = 600 kcal → 600 ÷ 9 = 66.7 g
Notes
- Food labels and tracking apps can round values, so totals may not match perfectly.
- Fiber, alcohol, and sugar alcohols can affect calorie counts in ways that do not fit neatly into the 4/4/9 rule.
- This is a planning tool, not a diagnosis. For official nutrition basics, see the USDA MyPlate guidance.