Macronutrient Partitioning
Macronutrient (Macro) Calculator
Distribute your daily calories into exact grams of Protein, Carbohydrates, and Healthy Fats using the Atwater energy system. Read our full macronutrient allocation framework on our Calculation Methodology page.
Don't know your calories? Use our TDEE Calculator first.
Protein (40%)
200g
800 kcal (4 kcal/g)
Carbs (30%)
150g
600 kcal (4 kcal/g)
Fats (30%)
67g
600 kcal (9 kcal/g)
Target Macros Per Meal (3 Meals Daily)
Calories
667 kcal
Protein
67g
Carbs
50g
Fats
22g
The Science of Macronutrient Energy Density
Macronutrients are metabolized at fixed energetic constants established by the Atwater General Factor System:
- Protein (4 kcal/g): Essential for cellular repair, enzyme production, and Muscle Protein Synthesis. Highest Thermic Effect of Food (TEF ~20–30%).
- Carbohydrates (4 kcal/g): Primary fuel source for glycolytic athletic output and central nervous system glucose metabolism.
- Fats (9 kcal/g): Critical for cell membrane integrity, fat-soluble vitamin absorption (A, D, E, K), and steroid hormone production (testosterone, estrogen).
Calculation Disclaimer: For informational and planning estimates only; not medical advice. Consult a healthcare professional before making major dietary changes. Read our full Medical Disclaimer and Calculation Methodology.
Generate Meals with These Exact Macros
Our AI meal planner will build 7 days of delicious recipes matched to your custom protein, carb, and fat targets.
Generate 7-Day Meal Plan