What Is Basal Metabolic Rate?
Your basal metabolic rate (BMR) is the number of calories your body burns at complete rest just to keep you alive: breathing, circulating blood, maintaining body temperature and repairing cells. It typically makes up 60–70% of the calories you burn each day.
This BMR calculator uses your sex, age, height and weight to estimate your BMR, then multiplies it by your activity level to estimate your Total Daily Energy Expenditure (TDEE), the calories you burn on a typical day.
The Mifflin-St Jeor Equation
Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5. Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161. Research has found Mifflin-St Jeor to be one of the most accurate BMR equations for most adults.
Example: a 30-year-old man who weighs 80 kg and is 180 cm tall has a BMR of about 1,780 calories. With moderate activity (×1.55), his TDEE is about 2,759 calories per day.
Activity Level Multipliers
- Sedentary (little or no exercise): × 1.2
- Lightly active (exercise 1–3 days/week): × 1.375
- Moderately active (exercise 3–5 days/week): × 1.55
- Very active (hard exercise 6–7 days/week): × 1.725
- Extra active (very hard exercise or a physical job): × 1.9
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is the calories you burn at complete rest. TDEE adds the calories burned through daily movement and exercise. Use TDEE, not BMR, as your maintenance calorie number.
Should I eat fewer calories than my BMR to lose weight?
Generally no. Eating below your BMR for long periods can be hard to sustain and may cost you muscle. A moderate deficit below your TDEE is a safer approach. Check with a healthcare provider before making big changes.
Why does BMR go down with age?
BMR tends to decline with age mainly because people lose muscle mass over time. Strength training and an active lifestyle can help maintain muscle and support your metabolism.