BMR Calculator
Free BMR calculator using Mifflin-St Jeor, Harris-Benedict and Katch-McArdle formulas, with a daily calorie (TDEE) table for every activity level.
About the BMR Calculator
BMR — basal metabolic rate — is the number of calories your body burns at complete rest just keeping you alive: breathing, circulation, cell repair. This free BMR calculator estimates it from your age, sex, height and weight using the two most trusted equations, Mifflin-St Jeor (10w + 6.25h − 5a + 5 for men, −161 for women) and the revised Harris-Benedict. Add your body-fat percentage and it also runs Katch-McArdle, which is based on lean mass.
BMR is the foundation of every diet plan: multiply it by an activity factor (1.2 sedentary up to 1.9 extremely active) to get your TDEE — total daily energy expenditure — which the tool shows in a ready-made table. Anyone planning weight loss or muscle gain, from Karachi to Kolkata, starts here before setting a calorie deficit or surplus. Everything runs privately in your browser.
How to Use the BMR Calculator
- 1Select your sex and enter age, height (cm) and weight (kg).
- 2Optionally add body-fat % to unlock the Katch-McArdle formula.
- 3Compare BMR results across the formulas.
- 4Use the activity table to find your daily maintenance calories (TDEE).
Frequently Asked Questions
How is BMR calculated with an example?
Mifflin-St Jeor for a 30-year-old man, 170 cm, 70 kg: 10×70 + 6.25×170 − 5×30 + 5 = 700 + 1,062.5 − 150 + 5 = 1,617.5 ≈ 1,618 kcal/day. A woman with the same stats gets 1,451.5 kcal (subtract 161 instead of adding 5).
What is the difference between BMR and TDEE?
BMR is calories burned at total rest; TDEE adds daily movement and exercise by multiplying BMR by an activity factor. A BMR of 1,618 kcal with moderate activity (×1.55) gives a TDEE of about 2,508 kcal — that is the intake that keeps your weight stable.
Which BMR formula is most accurate?
Mifflin-St Jeor is the most accurate for the general population and is what dietitians usually use, which is why it is the highlighted result. Katch-McArdle can beat it if you know your body-fat percentage accurately, since it works from lean mass: BMR = 370 + 21.6 × lean mass in kg.
How do I use BMR to lose weight?
Find your TDEE first, then eat below it. With a TDEE of 2,500 kcal, eating 2,000 kcal creates a 500 kcal daily deficit — roughly 0.5 kg of fat loss per week (about 3,850 kcal per half kg). Our calorie deficit calculator turns a goal and timeframe into a daily target.
Why is my BMR different from what my smartwatch says?
Wearables estimate with their own formulas plus heart-rate data, and all methods are ±10% or so for individuals. Genetics, thyroid function, muscle mass and recent dieting all shift real metabolic rate. Use the number as a starting point and calibrate against 2-3 weeks of actual weight change.