Macro Calculator
Mifflin-St Jeor BMR · activity · goal · protein-first split
Starting estimates — reassess against measured results over two to three weeks and adjust.
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How the numbers are built
Your basal metabolic rate is estimated with the Mifflin-St Jeor equation, then multiplied by an activity factor to reach maintenance calories (TDEE). A fat-loss goal drops that ~20%, a muscle-building goal adds ~12%. Protein is set first at roughly 2.2 g per kg of bodyweight, fat at ~25% of calories, and carbohydrate fills the remainder.
Why protein-first
Protein anchors the split because it is the macronutrient most tied to retaining lean mass in a deficit and building it in a surplus. Once protein and a floor of dietary fat are set, carbohydrate is the flexible lever you adjust week to week based on results, training energy, and hunger.
General-population estimate, not medical or nutritional advice. Individual needs vary with body composition, health conditions, and training. Consult a qualified professional before making significant dietary changes.