BMR Calculator

Calculate your basal metabolic rate with the Mifflin-St Jeor, Harris-Benedict and Katch-McArdle formulas — and the calories you burn at each activity level.

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BMR (Mifflin-St Jeor)—calories a day at complete rest
Harris-Benedict
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Katch-McArdle
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Calories burned per day (TDEE)

BMR calculator

Your basal metabolic rate (BMR) is the number of calories your body needs just to stay alive at rest. It is the foundation of every diet plan: once you know it, you can work out how much you burn in a normal day and how much to eat to lose, maintain or gain weight. This BMR calculator shows the result from the three most-used formulas side by side, plus your daily calorie burn at five activity levels.

How to use it

  1. Enter your sex, age, height and weight.
  2. Optionally add your body-fat percentage for the Katch-McArdle formula.
  3. Find your activity level in the table to see your daily calorie burn.

Formulas

Mifflin-St Jeor: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (men) or − 161 (women)

Katch-McArdle: 370 + 21.6 × lean body mass (kg)

Example

A 30-year-old man, 170 cm and 70 kg, has a BMR of 10 × 70 + 6.25 × 170 − 5 × 30 + 5 =1,618 calories a day. With a moderately active lifestyle (× 1.55) he burns about2,508 calories a day, so eating around 2,500 maintains his weight. A woman of the same age, height and weight has a BMR of about 1,452. Turn this into a diet target with thecalorie calculator, and check your weight band with theBMI calculator.

Health disclaimer: This tool gives general estimates for information only and is not medical advice, diagnosis or treatment. Please consult a qualified doctor about your health. Read the full disclaimer.

Frequently asked questions

What is BMR?
Basal metabolic rate is the energy your body uses at complete rest — breathing, circulation, keeping warm and running your organs. It is usually 60–70% of the calories you burn in a day.
Which BMR formula is most accurate?
Mifflin-St Jeor (1990) is considered the most reliable for most adults and is the default here. Harris-Benedict tends to give slightly higher numbers. Katch-McArdle uses lean body mass, so it can be better for lean, muscular people if you know your body-fat percentage.
How is BMR different from TDEE?
TDEE (total daily energy expenditure) adds your activity on top of BMR — walking, work and exercise. TDEE = BMR × activity factor. Use the calorie calculator to turn your BMR into a daily calorie target for losing or gaining weight.
Should I eat less than my BMR to lose weight?
Generally no. Eating well below BMR for long periods can cause muscle loss, fatigue and nutrient gaps. A moderate deficit below your TDEE is safer. Speak to a doctor or registered dietitian before a strict diet.

Calorie Calculator (TDEE)

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