Macro Calculator for Athletes

Step 1: BMR. Harris-Benedict from your sex, age, height, and weight — the calories you burn at rest.

Step 2: Maintenance. BMR × an activity multiplier from 1.2 (almost no activity) to 1.9 (10+ hours a week).

Step 3: Goal. Maintain holds calories at maintenance. Gain adds 250 kcal/day (~0.5 lb/week). Lean out subtracts 500 kcal/day (~1 lb/week, capped at 1% of bodyweight per week). Targets never drop below 1,500 kcal for men or 1,200 kcal for women.

Step 4: Macros. Protein is set first at 1.2 g per lb of bodyweight. The remaining calories split 50/50 between carbs (4 kcal/g) and fat (9 kcal/g).

1.2 g per lb (about 2.6 g/kg). A 180 lb lifter lands at 216 g a day. That sits at the high end of the research range on purpose: it covers recovery from heavy strength work and conditioning in the same week, and it protects muscle when calories are lower.

Split it across 4–5 meals of 40–50 g. Hitting the daily number matters more than perfect timing — consistency is what moves strength and body composition.

0 days → ×1.2. 1–2 → ×1.375. 3–4 → ×1.55. 5–6 → ×1.725. 7 → ×1.9. Training days set your activity multiplier, assuming roughly an hour per session. Two-a-days, a physical job, or 15k+ daily steps? Bump the activity level up one notch.

Going from 3 to 5 sessions a week adds roughly 10% to maintenance — almost all of it should come back as carbs, the fuel for high-output work. Re-run the numbers when your schedule changes, and check bodyweight trend over 2–3 weeks before adjusting again.