Macro calculator

1. It estimates your BMR with the Mifflin-St Jeor equation

Your basal metabolic rate, or BMR, is roughly what your body burns at complete rest. The Mifflin-St Jeor equation is a widely used way to estimate it from weight, height, age, and sex. It is an estimate, and individual metabolisms vary, but it is a solid, well-studied starting point.

2. It multiplies by your activity level

BMR times an activity multiplier gives your estimated maintenance calories, the intake at which your weight would roughly hold steady. The multipliers range from 1.2 for a mostly seated life to 1.9 for hard daily training. Most people who lift 3 to 5 times a week and sit the rest of the day land near the middle. If you are unsure, pick the lower option; it is easier to add calories later than to undo an overestimate.

3. It adjusts for your goal, conservatively

A cut here means about 10 to 20 percent below maintenance, and a build means about 5 to 15 percent above it. Those moderate adjustments are sustainable for most people and leave room to adapt based on what actually happens. Aggressive deficits look faster on paper, but they are harder to stick to and harder to fuel training with. How your body responds is individual, so treat the target as a hypothesis to test, not a promise.

4. It splits calories into protein, carbs, and fat

Protein and carbs are counted at about 4 calories per gram and fat at about 9. Balanced (30/40/30) suits most people. Higher protein (40/30/30) is popular while cutting because protein is filling and supports muscle. Keto-leaning (30/10/60) keeps carbs low for people who prefer eating that way; check that the protein number still lands near 0.7 to 1 gram per pound of body weight, and adjust if you need to.