BMR Calculator (3 Formulas)
Estimate resting calorie burn using Mifflin-St Jeor (default), Harris-Benedict revised, and Katch-McArdle (uses lean body mass for highest accuracy).
HEALTHEstimate calories burned at rest using three formulas: Mifflin-St Jeor (modern default), Harris-Benedict revised (1984), and Katch-McArdle (uses lean body mass — most accurate if you know body fat %).
BMR is calories your body burns at rest just keeping organs running. Multiply by an activity multiplier (1.2 sedentary → 1.9 athlete) to get TDEE (total daily energy expenditure). Mifflin-St Jeor is the most validated for the general adult population; Katch-McArdle is best for athletes; Harris-Benedict tends to overestimate.
BMR Calculator (Basal Metabolic Rate)
Estimate calories burned at rest using three formulas: Mifflin-St Jeor (modern default), Harris-Benedict revised, and Katch-McArdle (uses lean body mass for highest accuracy if you know your body fat %).
BMR vs TDEE
BMR is calories your body burns at rest (organs working, breathing). TDEE = BMR × activity multiplier (1.2 sedentary → 1.9 athlete) and represents your total daily burn including movement and exercise. Use the TDEE Calculator to apply an activity multiplier and get macro recommendations.
Predictive equations have ±10% error vs measured BMR (indirect calorimetry). Mifflin-St Jeor is the most validated for the general adult population; Katch-McArdle is best for athletes with known body fat percentage; Harris-Benedict tends to overestimate.