How Macros Are Calculated
The calculator uses three steps: estimate BMR with the Mifflin-St Jeor equation, multiply by an activity factor to get TDEE, adjust total calories by goal, then split into protein, fat, and carbohydrates.
Macro Splits by Goal
| Goal | Calorie Adjustment | Protein | Fat | Carbs |
|---|---|---|---|---|
| Fat Loss | −500 cal/day | 35–40% | 25–30% | 30–35% |
| Maintenance | 0 | 25–30% | 25–30% | 40–50% |
| Muscle Gain | +300 cal/day | 30–35% | 20–25% | 40–50% |
Why Protein Is Set First
Protein preserves lean mass during a calorie deficit and supports muscle synthesis during a surplus. Research supports 0.7–1.0 g per pound of body weight for active people. Set protein first, then fat (for hormones and satiety), then fill remaining calories with carbohydrates. Track your lean mass with our LBM calculator to refine your protein target.