BMR Calculator — Basal Metabolic Rate (3 Formulas Compared)
Calculate your Basal Metabolic Rate using Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas. See TDEE for each activity level. Metric and imperial.
Mifflin-St Jeor BMR (Recommended)
1,618
calories / day at rest
Harris-Benedict BMR
1,672
calories / day at rest
TDEE by Activity Level (Mifflin-St Jeor)
1.2×
1,941
1.375×
2,224
1.55×
2,507
1.725×
2,790
1.9×
3,073
All calculations are estimates. Consult a registered dietitian for personalised nutrition advice.
Related Tools
More free utilities you might find useful
Frequently Asked Questions
Quick answers to common questions
What is BMR and why does it matter for fitness?+
Basal Metabolic Rate (BMR) is the calories your body burns at complete rest for vital functions. BMR accounts for 60-70% of total daily calorie expenditure. Knowing your BMR helps set accurate calorie targets for weight loss, gain, or maintenance.
Which BMR formula is the most accurate?+
The Mifflin-St Jeor equation (1990) is recommended by the American Dietetic Association — it is within 10% of measured resting metabolic rate for 82% of individuals. Harris-Benedict tends to overestimate by about 5%. Katch-McArdle is most accurate if you know your lean body mass.
How do I calculate my daily calorie needs from BMR?+
Multiply BMR by activity multiplier: Sedentary = BMR × 1.2, Lightly active = BMR × 1.375, Moderately active = BMR × 1.55, Very active = BMR × 1.725.