Metabolic Rate Calculator

BMR is the number of calories your body burns at rest to maintain basic life functions like breathing, circulation, cell production, and temperature regulation. It represents 60-70% of your total daily calorie expenditure.

BMR is calories burned at complete rest, while TDEE includes BMR plus calories burned through physical activity and exercise. TDEE gives you a more practical number for daily calorie needs.

This calculator uses the Mifflin-St Jeor equation, which is considered one of the most accurate BMR formulas. For men: BMR = 10 × weight + 6.25 × height - 5 × age + 5. For women: BMR = 10 × weight + 6.25 × height - 5 × age - 161.

Your BMR is influenced by age, weight, height, gender, muscle mass, genetics, hormones, environmental temperature, and overall health. Men typically have higher BMRs than women due to greater muscle mass.

To lose weight, consume fewer calories than your TDEE. To gain weight, consume more calories than your TDEE. To maintain weight, match your calorie intake to your TDEE. A deficit or surplus of 500 calories per day typically results in 1 pound weight change per week.

BMR and RMR are very similar and often used interchangeably. BMR is measured under strict laboratory conditions after 12 hours of fasting, while RMR is measured under less restrictive conditions and is slightly higher than BMR.

BMR calculations provide good estimates but can vary by 10-15% between individuals due to factors like genetics, body composition, and health conditions. For precise measurements, indirect calorimetry testing is needed.

Yes, BMR typically decreases with age due to loss of muscle mass and changes in hormone levels. BMR generally decreases by about 2-3% per decade after age 20, which is why calorie needs often decrease as we get older.