What is BMR? Complete Guide to Basal Metabolic Rate
Your Basal Metabolic Rate (BMR) represents the minimum number of calories your body needs to sustain basic life functions while at complete rest. Think of it as the "idle speed" of your body's engine — the energy required for breathing, maintaining body temperature, circulating blood, and keeping your organs functioning.
The Mifflin-St Jeor Formula
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Factors That Affect Your BMR
- 🧬 Genetics: Natural metabolic rate varies from person to person, partly due to genetic factors.
- 💪 Muscle mass: Muscle tissue burns more calories at rest than fat tissue. More muscle = higher BMR.
- 📅 Age: BMR decreases with age, roughly 2–3% per decade after age 20.
- ⚧ Sex: Men typically have higher BMR than women due to greater muscle mass.
- 🌡️ Hormones: Thyroid hormones play a major role in regulating metabolic rate.
BMR vs. TDEE: What's the Difference?
BMR is just your resting calorie need. Your Total Daily Energy Expenditure (TDEE) accounts for your activity level on top of BMR. To maintain your current weight, you should eat approximately your TDEE. To lose weight, eat 300–500 calories below TDEE. To gain weight, eat 300–500 calories above TDEE. Use our Calorie Calculator for a full TDEE breakdown.