Macro Nutrient Calculator
The Macro Nutrient Calculator estimates your daily calorie needs and macronutrient breakdown based on age, weight, height, and activity level. This tool helps fitness enthusiasts and dieters optimize their diet for specific body composition goals. Whether you are trying to lose fat, maintain weight, or gain muscle, this calculator provides a clear roadmap to fuel your body correctly. It takes the guesswork out of meal planning by giving you exact gram targets.
How Daily Needs and Macros Are Calculated
Your daily needs represent the total energy your body burns and how that energy splits into protein, carbs, and fats. We calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, which is widely considered the most accurate formula for healthy adults.
TDEE = BMR (Mifflin-St Jeor) × Activity Factor
Where:
- BMR: Calories burned at complete rest based on weight, height, age, and gender.
- Activity Factor: Multiplier ranging from 1.2 (sedentary) to 1.9 (extra active).
- Goal Adjustment: TDEE is multiplied by 0.85 (loss), 1.0 (maintain), or 1.1 (gain).
First, we multiply your BMR by your activity level to find your Total Daily Energy Expenditure (TDEE). Next, we adjust this total by your fitness goal to create a calorie surplus or deficit. Finally, we divide these calories into grams using your selected protein percentage, splitting the remaining calories between fats and carbohydrates.
What Your Daily Needs and Macros Mean
This result tells you exactly how much to eat daily to change your body shape effectively. By hitting these specific targets, you ensure your body has the right building blocks for your goals.
Lose Fat
Aim for a calorie target roughly 15% below your TDEE. For example, if your maintenance is 2,500 kcal, eat around 2,125 kcal. Prioritize hitting your protein grams (e.g., 160g) to keep you full and protect your muscles while in a deficit.
Gain Muscle
Target a calorie surplus of about 10% above your TDEE. If your maintenance is 2,500, aim for 2,750 kcal. Focus on carbohydrates to fuel heavy lifting sessions, ensuring the extra energy supports growth rather than fat storage.
These figures are for informational purposes only and do not constitute medical advice. Individual nutritional needs vary based on health history and genetics, so please consult a registered dietitian or healthcare provider before starting a new diet plan.
Monitor your weight and energy levels weekly for 4 weeks. If you are not seeing changes, adjust your daily calories by 100-200 kcal and recalculate.