Nutrition

BMR & Calorie Calculator

Calculate your Basal Metabolic Rate and daily calorie needs based on your activity level.

Weight (kg)

Height (cm)

Age

Biological sex

Activity level

What is Basal Metabolic Rate (BMR)?

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions at complete rest — breathing, circulation, cell production and temperature regulation. It represents 60–75% of total daily energy expenditure and is the foundation for calculating nutritional needs.

How is it calculated?

Two validated formulas are used: Mifflin-St Jeor (1990), considered the most accurate for modern populations, and Harris-Benedict (revised 1984). Both use weight, height, age and biological sex. The result is multiplied by an activity factor to obtain TDEE.

Formula

Mifflin (men): BMR = 10×W + 6.25×H − 5×A + 5 Mifflin (women): BMR = 10×W + 6.25×H − 5×A − 161

⚠️ Limitations

These formulas provide estimates with a margin of ±10%. They are less accurate for people with atypical body compositions (very high muscle mass or obesity). Pregnant or breastfeeding women require individual adjustments.

FAQ

What is the difference between BMR and TDEE?

BMR is the energy your body burns at complete rest. TDEE adds physical activity and the thermic effect of food on top of BMR.

Which formula is more accurate, Harris-Benedict or Mifflin-St Jeor?

Mifflin-St Jeor (1990) is generally considered more accurate for modern populations. Harris-Benedict tends to overestimate slightly.

Do I need to eat my BMR calories as a minimum?

Eating below your BMR long-term is not recommended as it can cause muscle loss and metabolic slowdown. A safe minimum is 80% of BMR.

How often should I recalculate my TDEE?

Recalculate every 4–6 weeks or whenever your weight, activity level or body composition changes significantly.