A BMR (Basal Metabolic Rate) calculator estimates the minimum number of calories your body needs at complete rest to maintain basic life functions like breathing, circulation, and cell production.
About this calculator
A BMR (Basal Metabolic Rate) calculator estimates the minimum number of calories your body needs at complete rest to maintain basic life functions like breathing, circulation, and cell production. BMR is the starting point for all calorie and nutrition planning.
The Mifflin-St Jeor equation, used in this calculator, is considered the most accurate BMR formula for most people: BMR = 10W + 6.25H − 5A + S, where W is weight in kg, H is height in cm, A is age in years, and S is +5 for males and −161 for females.
Common uses
- Calculate minimum calorie needs before determining total daily calorie intake
- Understand how age and body composition affect metabolic rate
- Use as a baseline for weight loss or muscle gain calorie planning
- Compare BMR across different Mifflin-St Jeor formula variations
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the calories burned at complete rest. TDEE (Total Daily Energy Expenditure) is BMR multiplied by an activity factor to account for movement, exercise, and daily activities. TDEE is the actual calorie intake needed to maintain your current weight.
Does BMR decrease with age?
Yes, BMR naturally decreases with age, typically by 1–2% per decade after age 30, primarily because muscle mass tends to decrease with age. Strength training helps preserve muscle mass and slow the decline in metabolic rate.