Accurate Macros Calculator

Accurate Macros Calculator

Protein, Fat, Carbs & Fibre

This may be the most accurate Macros Calculator online. It's designed to help you work out your macronutrient requirements for your body.

Try our Accurate TDEE Calculator to get your Total Daily Energy Expenditure.

What are macronutrients?

Macronutrients — protein, fat, and carbohydrates — are the three main nutrients your body needs in large quantities. Each plays a different role: protein builds and repairs muscle, fat supports hormone function, and carbs provide energy.

Getting the right balance of macros is just as important as total calorie intake. Your ideal macro split depends on your body composition, activity level, and fitness goals.

How are macros calculated?

Protein is calculated based on your lean body mass. If you provide your body fat percentage, protein is set at 1g per pound of lean mass. Without body fat data, it defaults to 1.8g per kilogram of body weight.

Fat is set at 25% of your total calorie target, then divided by 9 to convert to grams (since fat contains 9 calories per gram).

Carbohydrates make up the remaining calories after protein and fat have been allocated, divided by 4 to convert to grams.

Fibre is calculated at 14g per 1,000 calories, which aligns with general dietary guidelines.

Why do macros matter for your goals?

For fat loss: Adequate protein intake helps preserve muscle mass while in a calorie deficit. Getting enough fat supports hormone production, and carbs fuel your training sessions.

For muscle gain: Higher protein intake supports muscle protein synthesis. A calorie surplus with the right macro balance ensures you build lean mass rather than just gaining fat.

For maintenance: A balanced macro split keeps your body composition stable while supporting energy levels and overall health.

What else does our free Macros Calculator do?

This Macros Calculator works out your full macronutrient breakdown alongside a complete body analysis including TDEE, BMR, BMI, body composition, ideal weight, heart rate zones, and more.