BMR Calculator

What it does

The basal metabolic rate (BMR) is the energy your body uses at complete rest to breathe, pump blood and keep its temperature: usually 60 to 70% of all the calories you burn. Mifflin-St Jeor is the equation most dietitians use today; Harris-Benedict is the classic one; Katch-McArdle uses lean body mass and suits people who know their body fat.

How to use it

1. Choose metric or imperial units and enter your sex, age, weight and height.
2. Add your body fat percentage if you know it, to see the Katch-McArdle result too.
3. Compare the equations, and pick an activity level to see your daily total.

The arithmetic runs in your browser. Nothing you type is sent anywhere and nothing is stored, so you can use these with real numbers.

Frequently asked questions

Which BMR equation is the most accurate?
For most adults, Mifflin-St Jeor: studies find it within 10% of the measured value more often than Harris-Benedict. For lean, muscular people who know their body fat, Katch-McArdle is often closer.

Why do the equations give different results?
They were fitted on different groups of people in different decades. Harris-Benedict, from 1919 and revised in 1984, tends to give a bit more than Mifflin-St Jeor, from 1990. A difference of 50 to 100 kcal is normal.

Should I eat less than my BMR to lose weight?
No. The BMR is only the energy at rest; your real daily need is higher. A deficit is calculated from your TDEE, and eating below your BMR for long is hard to sustain and is not recommended without medical supervision.

Is this medical advice?
No. It is a general estimate for healthy adults. If you are pregnant, ill, under 18 or planning a large change in diet, talk to a doctor or a dietitian.

🔥 TDEE Calculator
🥗 Macro Calculator
📏 Body Fat Calculator
🍎 Calorie Calculator

Wikipedia — Basal metabolic rate
Wikipedia — Harris–Benedict equation
Wikipedia — Physical activity level