RMR (or BMR) is the energy your body uses to keep the lights on: breathing, heart, brain, temperature. It's the biggest slice of your daily calorie burn.
Lean mass is the biggest lever. 10 extra pounds of muscle add ~50–70 kcal to daily RMR.
Age slowly lowers RMR (~1–2% per decade), largely because muscle mass tends to drop.
Men: 10×kg + 6.25×cm − 5×age + 5. Women: 10×kg + 6.25×cm − 5×age − 161.
Multiply by an activity factor to get TDEE — the number you actually plan meals around.
Get your RMR and TDEE in one calculation.
Calorie / TDEE Calculator →
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