Calculate Your BMR

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions at rest. These functions include breathing, circulation, nutrient processing, and cell production.

BMR accounts for about 60-75% of your daily calorie expenditure. It's the foundation for understanding your total daily energy needs and is essential for weight management planning.

Common BMR Formulas

Mifflin-St Jeor (Recommended):
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5
Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
Harris-Benedict:
Men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) - (5.677 × age in years)
Women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) - (4.330 × age in years)
Katch-McArdle:
BMR = 370 + (21.6 × lean body mass in kg)
Note: Requires body fat percentage. More accurate for lean individuals.

Factors Affecting BMR

  • Age: BMR decreases by about 2% per decade after age 20
  • Gender: Men typically have higher BMR than women due to greater muscle mass
  • Body Composition: More muscle mass = higher BMR
  • Genetics: Some people naturally have faster or slower metabolism
  • Hormones: Thyroid hormones significantly affect metabolic rate
  • Environmental Temperature: Extreme temperatures can increase BMR
  • Health Status: Illness, fever, or recovery can temporarily increase BMR

How to Use Your BMR

Your BMR is the starting point for calculating your Total Daily Energy Expenditure (TDEE). To find your TDEE, multiply your BMR by an activity factor:

  • Sedentary (little or no exercise): BMR × 1.2
  • Lightly active (light exercise 1-3 days/week): BMR × 1.375
  • Moderately active (moderate exercise 3-5 days/week): BMR × 1.55
  • Very active (hard exercise 6-7 days/week): BMR × 1.725
  • Extremely active (very hard exercise & physical job): BMR × 1.9

Important Notes

  • BMR calculators provide estimates - actual BMR can vary by 10-15%
  • Medical conditions (thyroid disorders, diabetes) can affect BMR
  • Severe calorie restriction can lower BMR over time
  • Building muscle through strength training can increase BMR
  • For most accurate results, consider professional metabolic testing

Next Steps

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