BMR Calculator: Estimate Basal Metabolic Rate
Basal metabolic rate (BMR) is a formula-based estimate of energy used at rest. This calculator uses age, height, weight, and a sex coefficient to provide a general estimate in kilocalories per day.
How to use this tool
- Select the sex used by the formula.
- Enter your age in years.
- Enter your weight and choose kilograms or pounds, then your height and choose centimetres, inches, feet or feet and inches.
- Choose Calculate to see the estimated daily BMR.
- Use the result only as a starting point for general information.
Options explained
This tool applies a common adult BMR formula. BMR is not the same as total daily energy expenditure; activity and individual health conditions affect overall energy needs.
Accuracy and limitations
This calculator is not medical advice, a diagnosis, or a meal plan. It may not be appropriate for children, pregnancy, athletes, or people with medical conditions. Consult a qualified healthcare professional for personal guidance.
The formula behind the number
The tool uses the Mifflin-St Jeor equation for adults: 10 times weight in kilograms, plus 6.25 times height in centimetres, minus 5 times age in years, then plus 5 for men or minus 161 for women. The result is the estimated number of calories the body uses at rest in a day. It is a formula-based estimate for an average person, not a measurement of your own body.
Worked examples
For a man of 30 who weighs 70 kg and is 175 cm tall, the sum is 700 + 1,093.75 - 150 + 5, which is about 1,649 calories a day. For a woman of 30 who weighs 60 kg and is 165 cm tall it is 600 + 1,031.25 - 150 - 161, which is about 1,320 calories a day. Your own number depends on your build, muscle mass, hormones and health.
BMR, activity and total energy
BMR is only the energy used at rest. Walking, work and exercise use more, so the energy you need over a whole day is higher. The Calorie Calculator multiplies the BMR by an activity factor to give a rough maintenance estimate. Neither number tells you how much you should eat, and a smartwatch or another calculator can give a different result because it uses a different method.
Units and limits
Choose the weight unit (kilograms or pounds) and the height unit (centimetres, inches, feet or feet and inches) next to the boxes, and the tool converts the numbers for you. The formula is meant for healthy adults, and it can be misleading for children, pregnant or breastfeeding women, athletes and people with medical conditions. Ask a doctor or a registered dietitian for advice about your own situation.
Frequently asked questions
Which formula does the calculator use?
The Mifflin-St Jeor equation, with +5 for men and -161 for women.
Is BMR the number of calories I should eat?
No. It is only the estimated energy used at rest. How much to eat depends on your activity, health and goals, so ask a professional.
Can I enter pounds or feet?
Yes. Choose pounds next to the weight box and inches, feet or feet and inches next to the height box. The tool converts them.
Why does a smartwatch give a different number?
Different devices and calculators use different formulas and assumptions, and all of them are estimates.
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