Health Calculator
BMR Calculator
Find out how many calories your body burns each day at rest — and adjust for your activity level.
What Is Basal Metabolic Rate (BMR)?
Your Basal Metabolic Rate is the number of calories your body needs to maintain basic physiological functions — breathing, circulation, cell production, and organ function — while completely at rest. BMR accounts for 60–70% of total daily energy expenditure for most people.
The Mifflin-St Jeor Formula
Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
TDEE vs BMR
TDEE (Total Daily Energy Expenditure) = BMR × Activity Multiplier. This is the number of calories you actually need each day. Eating below your TDEE causes weight loss; eating above causes weight gain.
How to Use Your BMR for Weight Management
- To lose weight: eat 300–500 kcal below your TDEE
- To gain muscle: eat 300–500 kcal above your TDEE with resistance training
- To maintain weight: eat at your TDEE
Frequently Asked Questions
Which BMR formula is most accurate?
The Mifflin-St Jeor equation (used here) is considered the most accurate for most adults. The Katch-McArdle formula is more accurate if you know your body fat percentage.
Does BMR change with age?
Yes. BMR typically decreases 1–2% per decade after age 20, primarily due to muscle mass loss. Strength training can slow this decline.
Why do men have a higher BMR than women?
Men generally have more muscle mass and less body fat than women of the same size and age. Muscle tissue burns more calories at rest than fat tissue.