BMR Calculator
1 lb = 0.4536 kg, 1 inch = 2.54 cm
How to use this BMR calculator
Using this free BMR calculator takes less than a minute. First, choose male or female. Next, enter your age in years, your weight in kilograms, and your height in centimetres. The result updates live on every change, so there is no button to press. If you normally think in pounds and inches, use the conversion note under the calculator: 1 lb equals 0.4536 kg, and 1 inch equals 2.54 cm, and then enter the metric figures, matching the TDEE Calculator on this site.
Worked examples
Take a man aged 30 years, 180 cm tall, weighing 80 kg. The Mifflin-St Jeor formula for men is 10 times weight, plus 6.25 times height, minus 5 times age, plus 5. That gives 800 plus 1,125 minus 150 plus 5, which equals 1,780 kcal per day. This matches the example used by the TDEE Calculator, so the two tools agree with each other. Try it above and you will see 1,780 kcal/day.
Now take a woman aged 25 years, 165 cm tall, weighing 60 kg. The formula for women is 10 times weight, plus 6.25 times height, minus 5 times age, minus 161. That gives 600 plus 1,031.25 minus 125 minus 161, which equals 1,345.25, rounded to 1,345 kcal per day. Again, try the figures in the calculator and you will see the same result, with the formula and your numbers shown.
What BMR means
BMR stands for basal metabolic rate. It is the number of calories your body would burn in a day if you stayed completely at rest, simply keeping yourself alive: breathing, keeping your heart beating, maintaining your body temperature, and running the basic work of your cells. It does not include walking, working, exercising, or even digesting food. That is why BMR is a baseline, not a total. Most people burn considerably more than their BMR in a normal day, because normal life involves movement.
Knowing your BMR is still useful. It gives you a realistic floor for your daily energy needs and a starting point for thinking about food and activity. If you eat far below your BMR for a long time, you are likely under-fuelling your body, which is one reason crash diets are hard to sustain. If you eat well above your total daily needs, the surplus is stored, mainly as fat. BMR alone does not tell you how much to eat, but it anchors the conversation in a real number rather than a guess.
BMR vs TDEE
TDEE, or total daily energy expenditure, is your BMR multiplied by an activity factor that reflects how much you move. A sedentary person might multiply BMR by about 1.2, while a very active person might use 1.7 or higher. The result is an estimate of the calories you actually burn in a day. That is why this page links to the TDEE Calculator: BMR tells you what you burn at rest, and TDEE tells you what you burn in real life. Use BMR when you want the baseline, and TDEE when you want a daily calorie target.
Please treat this BMR calculator as an estimate only, not medical advice. The Mifflin-St Jeor equation is widely used and well validated for typical adults, but it cannot account for your individual muscle mass, medical conditions, medicines, or metabolism. If you need personal guidance about weight, nutrition, or health, talk to a healthcare professional.
Frequently asked questions
What is BMR?
BMR is your basal metabolic rate: the calories your body burns at complete rest in a day, just to stay alive. It covers breathing, circulation, temperature control, and basic cellular work, and it excludes all activity.
Which formula does this calculator use?
It uses the Mifflin-St Jeor equation, the same formula as the TDEE Calculator on this site. For men it is 10W + 6.25H – 5A + 5, and for women it is 10W + 6.25H – 5A – 161, where W is weight in kilograms, H is height in centimetres, and A is age in years.
Why is BMR different for men and women?
On average, men have more muscle mass and less body fat than women of the same weight, and muscle burns more energy at rest than fat. The formula reflects that average difference with a different constant: plus 5 for men and minus 161 for women. It is a population average, not a rule about any individual.
Does muscle change BMR?
Yes. Muscle tissue is more metabolically active than fat tissue, so two people of the same weight can have different BMRs if one is much more muscular. The Mifflin-St Jeor equation does not measure body composition, which is one reason its result is an estimate.
Is the result exact?
No. It is a good estimate for most adults, but your true BMR can differ because of muscle mass, health, medicines, and other factors. Treat the figure as a starting point, and talk to a healthcare professional for personal guidance.