How to use the BMR calculator
Enter your details, tell us how active you are, and you are done. We can then estimate your basal metabolism and how much you burn during a normal day.
- 1Select the metric or imperial system.
- 2Enter your weight, height, age, and sex.
- 3Choose your activity level and press “Calculate BMR”.
BMR guide
What is basal metabolic rate?
Even if you stayed in bed all day without doing absolutely anything, your body would still use energy. It has to breathe, keep your heart working, regulate your temperature, fuel your organs... it cannot simply switch off. Basal metabolic rate, or BMR, tries to estimate how many calories your body needs to keep all of that running.
What BMR includes
Breathing, pumping blood, maintaining body temperature, keeping the brain, kidneys, liver, and other organs working... all of that needs energy. That is what your BMR tries to represent.
And walking, working, training, or climbing three flights of stairs? That is something else. BMR does not include it; that activity is added later when we calculate your daily expenditure.
How it is calculated
Measuring your metabolism exactly takes much more than a web calculator, so here we make an estimate. We use the Mifflin-St Jeor equation, which takes your weight, height, age, and sex to calculate an approximate value.
If you use pounds, feet, and inches, do not worry: we convert everything underneath and apply the same formula. You only need to enter the details.
BMR and total daily energy expenditure
Alright... this is where the confusion usually starts. BMR and TDEE are similar, but they answer different questions.
BMR is roughly answering: “How much does my body burn just by being alive and working?”
TDEE answers: “Great, and now that I got out of bed, walked, worked, exercised, and lived my day... how much did I burn in total?”
That is why you can change your activity level and see that BMR barely changes while TDEE does. Your physical details stayed the same; what changed was how much you move.
How to interpret the result
Suppose your BMR comes out to 1,600 kcal. Does that mean you should eat exactly 1,600 kcal? No. That number is trying to represent what your body would burn at rest.
Now imagine that, after including your activity, TDEE rises to 2,200 kcal. That figure is already trying to get closer to what you burn during a complete day.
Is it exactly 2,200? Not that either. Your body does not read the calculator. Your actual activity, body composition, and other individual differences can move that number up or down. Use it as a starting reference, not a number carved in stone.
The calculation happens in your browser
Your details are used in your browser to do the calculation. You do not need an account or to send them to a calculation server. Enter the numbers, we calculate, and that is it.
Questions about the BMR calculator
What is the difference between BMR and TDEE?
BMR estimates what your body burns at rest. TDEE takes that number and adds an estimate of everything you do during the day. If you want to get close to your total daily expenditure, TDEE is usually the number you are looking for.
Which equation does the calculator use?
We use the Mifflin-St Jeor equation. It considers your weight, height, age, and sex to estimate your basal metabolism.
Can I use pounds, feet, and inches?
Yes. Select “Imperial”, enter your weight in pounds and your height in feet and inches. We do the conversion; you do not need to take out a calculator to use the calculator.
Is the result medical advice?
No. It is a mathematical estimate of your metabolism and daily expenditure. It is useful as a reference, but it does not replace a clinical measurement or a personalised eating plan.
If you are adjusting your diet because of a health condition, pregnancy, or a goal that needs professional supervision, this calculator can give you context, but it should not be your only reference for deciding what to eat.