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 accounts for 60-75% of total daily calorie burn for most people.

Which BMR formula is more accurate?

The Mifflin-St Jeor equation (1990) is generally considered more accurate than the original Harris-Benedict equation (1919) for modern populations. Studies show it is accurate within 10% for most non-obese adults.

What is the difference between BMR and TDEE?

BMR is your calorie burn at complete rest. TDEE multiplies BMR by an activity factor to account for movement and exercise. TDEE is what you use to set calorie intake goals — not BMR directly.

Does BMR change over time?

Yes. BMR decreases with age (roughly 1-2% per decade after age 30) and changes with body composition — more muscle mass increases BMR. Significant calorie restriction also lowers BMR as the body adapts.

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BMR Calculator — Basal Metabolic Rate

Calculate your Basal Metabolic Rate (BMR) using Mifflin-St Jeor and Harris-Benedict formulas. Free BMR calculator with TDEE estimates for all activity levels.

Age: 30yr

Weight: 75kg

Height: 175cm

About This Tool

Calculate your Basal Metabolic Rate (BMR) using both the Mifflin-St Jeor and Harris-Benedict formulas. See TDEE estimates for every activity level from sedentary to very active.