Basal Metabolic Rate is the minimum number of calories needed to keep your body functioning at rest. It accounts for 60–75% of total calorie burn for most sedentary people.

Mifflin-St Jeor vs Harris-Benedict — which is better?

A 2005 study in the Journal of the American Dietetic Association found Mifflin-St Jeor predicted RMR within 10% for 82% of subjects, vs 70% for Harris-Benedict. Most dietitians now prefer Mifflin-St Jeor.

Does BMR change with age?

Yes — BMR decreases roughly 1–2% per decade after age 20, primarily due to loss of lean muscle mass. Resistance training slows this decline.

Is BMR the same as RMR?

Nearly. RMR (Resting Metabolic Rate) is slightly higher because it's measured under less strict conditions. For practical calorie-planning purposes, treat them as the same.

BMR Calculator

Enter your sex, age, height, and weight to see your BMR — how many calories you burn at rest before any activity.

BMR is the number of calories your body burns at complete rest just to keep basic functions running — breathing, circulation, cell repair. It's the foundation of every calorie budget. This calculator shows results from both the Mifflin-St Jeor equation (more accurate, recommended by dietitians) and the classic Harris-Benedict formula.

Last reviewed: April 2026Report an error

Sex

Age

Height

Weight (lbs)

BMR (Mifflin-St Jeor)

1,783 cal/day

Your BMR is 1,783 calories/day (Mifflin-St Jeor). You burn this many calories at complete rest — before any activity.

Mifflin-St Jeor (recommended)

1,783 cal/day

Harris-Benedict (classic)

1,865 cal/day

The Formula

BMR = 10W + 6.25H − 5A + S

W = Weight in kg
H = Height in cm
A = Age in years
S = +5 for men, −161 for women

Source: Journal of the American Dietetic Association — Mifflin-St Jeor vs Harris-Benedict ↗

How we verify our formulas →

How to Use This BMR Calculator

Select your biological sex.
Enter your age in years.
Enter your height and weight (metric or imperial).
Read your Mifflin-St Jeor BMR — this is the recommended figure.
Compare with the Harris-Benedict result; most people are within 50–100 calories of each other.

Frequently Asked Questions

: Basal Metabolic Rate is the minimum number of calories needed to keep your body functioning at rest. It accounts for 60–75% of total calorie burn for most sedentary people.
: A 2005 study in the Journal of the American Dietetic Association found Mifflin-St Jeor predicted RMR within 10% for 82% of subjects, vs 70% for Harris-Benedict. Most dietitians now prefer Mifflin-St Jeor.
: Yes — BMR decreases roughly 1–2% per decade after age 20, primarily due to loss of lean muscle mass. Resistance training slows this decline.
: Nearly. RMR (Resting Metabolic Rate) is slightly higher because it's measured under less strict conditions. For practical calorie-planning purposes, treat them as the same.

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