Metric (cm, kg)
Imperial (ft/in, lbs)
- Calories per day (Mifflin-St Jeor)

BMR Comparison (Different Formulas)

Mifflin-St Jeor
-
Most accurate
Harris-Benedict
-
Traditional
Katch-McArdle
-
Lean body mass

📚 Understanding BMR

What is BMR? Basal Metabolic Rate is the number of calories your body needs to perform basic functions like breathing, circulation, cell production, and nutrient processing while at rest.

BMR vs RMR: BMR is measured under strict conditions, while RMR (Resting Metabolic Rate) is more practical and typically 10-20% higher than BMR.

Factors affecting BMR:

  • Age: BMR decreases by about 2% per decade after age 20
  • Gender: Men typically have higher BMR due to more muscle mass
  • Body composition: Muscle tissue burns more calories than fat tissue
  • Genetics: Can account for up to 30% of BMR variation
  • Hormones: Thyroid hormones significantly affect metabolic rate

Formula Comparison:

  • Mifflin-St Jeor: Most accurate for general population (±10%)
  • Harris-Benedict: Older formula, tends to overestimate by 5%
  • Katch-McArdle: Best for lean individuals, requires body fat %

⚠️ BMR calculations are estimates. Individual variations can be significant. For precise measurements, consider indirect calorimetry testing.