BMR & TDEE Calculator
Calculate your Basal Metabolic Rate (BMR) and see your TDEE across all activity levels. Uses Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas.
What Is BMR (Basal Metabolic Rate)?
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform its most basic life-sustaining functions — breathing, circulation, cell production, and organ function — while at complete rest.
BMR accounts for approximately 60–70% of your total daily calorie expenditure. Understanding your BMR is the first step to calculating your TDEE and setting the right calorie targets for your fitness goals.
BMR vs TDEE: What's the Difference?
BMR is calories burned at rest. TDEE is your total daily calorie burn including all activity. To get your TDEE, multiply your BMR by an activity factor (1.2–2.0 depending on your lifestyle).
Want full calorie targets for weight loss or muscle gain? Use our TDEE Calculator which combines BMR with your activity level for a complete nutrition plan.
BMR Formula Comparison
Three main formulas are used to calculate BMR:
- Mifflin-St Jeor (1990) — Most accurate for general population. Validated against indirect calorimetry in multiple studies.
- Harris-Benedict Revised (1984) — Classic formula, slightly less accurate than Mifflin for modern populations but widely used.
- Katch-McArdle (1996) — Most accurate if you know your body fat %. Accounts for lean body mass directly.