Macro Calculator (Protein, Carbs & Fat)

This macro calculator turns four choices — your body data, activity level, goal and diet style — into a complete daily nutrition target: total calories plus protein, carbohydrate and fat in grams. It starts exactly like our calorie calculator: the Mifflin-St Jeor equation estimates your BMR (10 × weight + 6.25 × height − 5 × age, +5 for men or −161 for women), and an activity multiplier from 1.2 (sedentary) to 1.9 (very active) converts it into TDEE, your maintenance calories. Everything runs in your browser; no body data is sent anywhere.

The goal setting then adjusts the budget: weight loss subtracts 500 kcal per day (about half a kilogram per week), muscle gain adds a moderate 300 kcal surplus, and maintenance keeps TDEE unchanged. The diet style decides how those calories divide between macronutrients: balanced (30% protein / 40% carbs / 30% fat), low-carb (40/20/40), high-protein (40/30/30) or keto (25/5/70). Grams follow from the standard energy densities — 4 kcal per gram of protein or carbohydrate and 9 kcal per gram of fat.

Numbers on a label are only useful if they survive contact with real meals, so the result also includes a per-meal breakdown for 3 and 4 meals a day. If your target is 150 g of protein, seeing "50 g per meal" makes the plan concrete: roughly a chicken breast and a serving of cottage cheese per sitting. Research on muscle protein synthesis favors spreading protein evenly across the day rather than loading it into dinner, and the split rows make that easy to follow.

Like every formula-based estimate, these targets are a starting point, not a prescription: real energy needs vary with muscle mass, genetics and daily movement, and macro splits are ranges rather than laws. Track your weight trend for two or three weeks and adjust calories by 100–200 kcal if progress stalls or races. For medical conditions, pregnancy or a history of disordered eating, build your nutrition plan with a doctor or registered dietitian.