BMR Calculator
Calculate your Basal Metabolic Rate and daily energy expenditure.
BMR Calculator
Your Basal Metabolic Rate (BMR) is the number of calories your body burns just to stay alive — breathing, pumping blood, and maintaining organ function at complete rest. It's the foundation of all calorie calculations.
How to Use This Calculator
- Enter your age, gender, height, and weight.
- Select the formula: Mifflin-St Jeor (recommended), Harris-Benedict, or Katch-McArdle (requires body fat %).
- Click Calculate to see your BMR.
- Multiply by your activity factor to get TDEE (use our TDEE Calculator).
BMR Formulas
Mifflin-St Jeor (most accurate for most people):
Men: BMR = 10W + 6.25H − 5A + 5
Women: BMR = 10W + 6.25H − 5A − 161
(W = weight in kg, H = height in cm, A = age in years)
Harris-Benedict (older, slightly overestimates):
Men: BMR = 88.362 + 13.397W + 4.799H − 5.677A
Women: BMR = 447.593 + 9.247W + 3.098H − 4.330A
Katch-McArdle (uses lean body mass — best if body fat is known):
BMR = 370 + 21.6 × LBM (lean body mass in kg)
Example Calculation
35-year-old male | 80 kg | 178 cm (Mifflin-St Jeor)
- BMR = 10(80) + 6.25(178) − 5(35) + 5
- = 800 + 1112.5 − 175 + 5 = 1,742.5 calories/day
- This is the minimum to sustain life at complete rest
Common Mistakes to Avoid
- Eating only BMR calories — BMR is the bare minimum at complete rest. Any activity above zero requires additional calories. Eating only BMR creates an unhealthy deficit unless you're bed-ridden.
- Assuming BMR is fixed — BMR decreases with age, with prolonged calorie restriction, and as body weight decreases. Recalculate whenever your stats change significantly.
- Using the same formula for everyone — Mifflin-St Jeor works best for average adults. Athletes with high muscle mass benefit from Katch-McArdle.
Frequently Asked Questions
What factors affect BMR?
Body weight (more weight = higher BMR), muscle mass (muscle burns more calories than fat), age (BMR decreases ~2% per decade after 25), gender (men generally have higher BMR due to greater muscle mass), and genetics.
Can I increase my BMR?
Yes — primarily through building muscle mass (resistance training). Each pound of muscle burns approximately 6 more calories/day at rest than fat. Over time, consistent strength training meaningfully raises BMR.
Is BMR the same as RMR?
Nearly — RMR (Resting Metabolic Rate) is measured under less strict conditions than BMR (which requires complete rest, fasting, and thermoneutral environment). RMR is typically 10–20% higher than true BMR and is what most formulas actually estimate.
Conclusion
Your BMR is the starting point for any nutrition plan. Calculate it here, then multiply by your activity level to get your true daily calorie needs. This foundation makes all other diet and fitness decisions more accurate and effective.
Related: TDEE Calculator | Calorie Calculator | Macro Calculator | BMI Calculator
Expert Tip
Muscle tissue burns more calories than fat even at rest. Increasing your lean muscle mass through strength training is a natural way to raise your BMR.
