Calculate adult BMI from metric or imperial measurements and compare WHO or Asian/Indian category cut-offs.
BMR Calculator
Estimate basal metabolic rate with the Mifflin-St Jeor, Harris-Benedict and Katch-McArdle equations.
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Basal metabolic rate estimates
Calories per day at rest. Compare estimates instead of treating any one equation as exact.
Mifflin-St Jeor
Harris-Benedict
Katch-McArdle
Estimated daily needs
| Equation | BMR | At selected activity |
|---|
These equations estimate resting energy use for adults. They are not medical advice and are not designed for pregnancy, children or conditions that affect metabolism.
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How to use BMR Calculator
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Step 1: Enter body details
Add your age, height, weight and the equation option that best fits your information.
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Step 2: Optional body-fat percentage
Add body fat only when you have a reasonable measurement to use the Katch-McArdle equation.
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Step 3: Compare estimates
Compare the BMR equations and use the activity table as a starting point, not a prescribed calorie target.
What BMR estimates show
Basal metabolic rate (BMR) estimates the energy your body uses at rest over a day. This calculator shows three common equations: Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle. Katch-McArdle uses lean body mass, so it needs a body-fat percentage.
The activity table multiplies each BMR estimate by a standard activity factor to provide a broad daily-energy estimate. It is not a calorie prescription. Training volume, illness, medication, sleep, pregnancy, body composition and normal individual variation can all make real energy needs different.
Use health information carefully
These formulas are screening estimates, not measurements. Indirect calorimetry is used for a measured resting metabolic rate. This calculator is for adults and is not designed for children, pregnancy or medical conditions that affect metabolism. Speak with a qualified health professional for medical, nutrition or weight-management advice.
Limitations
- The equations estimate resting energy use; a measured value can differ noticeably.
- Results are for adults and are not designed for children or pregnancy.
- Medical conditions, medicines and body composition can affect energy needs.
- Activity estimates are broad starting points, not personalised calorie advice.
Frequently asked questions
Which BMR equation should I use?
Mifflin-St Jeor and revised Harris-Benedict are common age, height and weight equations. Katch-McArdle can be useful when you have a reliable body-fat percentage. Compare them rather than treating one as exact.
Is BMR the same as daily calorie needs?
No. BMR estimates energy at rest. Daily needs also depend on movement, exercise and other factors, which is why the calculator shows activity-level estimates separately.
Can I use this during pregnancy?
No. Pregnancy changes energy needs in ways these equations do not model. Discuss personal guidance with a qualified health professional.
Related tools
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