What does this BMR calculator estimate?
This BMR calculator gives an equation-based estimate of the energy your body uses at rest, expressed as kilocalories per day (kcal/day). It uses the Mifflin–St Jeor resting energy equation with the weight, height, age and coefficient you enter.
The result is a starting point for understanding resting energy use. It is not a measurement of your metabolism, a complete daily calorie allowance or a personalised eating plan. Everyday movement and exercise are not included in this resting estimate.
How to use the calculator
Enter your current weight in kilograms and your height in centimetres. Enter your age in whole adult years, then select the equation coefficient you want to use. Check the units before running the calculation: a height of 1.70 metres should be entered as 170 centimetres.
Select Run tool to see the result. Review your inputs alongside the estimated resting calories. If you change a value, run the calculator again so the result reflects the new information. Reset restores the tool’s starting values.
Calculations run in your browser. Review the result before saving or printing a copy. A saved report is useful for keeping the inputs and result together; it does not turn an estimate into a clinical measurement.
The equation used on this page
The calculation is: 10 × weight in kilograms + 6.25 × height in centimetres − 5 × age in years + the selected coefficient. The male coefficient adds 5; the female coefficient subtracts 161.
The tool rounds the final resting-calorie result to the nearest whole kilocalorie. These are the coefficients used by the equation, rather than a measurement of your individual body composition. The original research reference is linked below.
Worked example
For an adult aged 30, weighing 70 kg and measuring 170 cm, the calculation with the male coefficient is 700 + 1,062.5 − 150 + 5 = 1,617.5 kcal/day. The displayed result is 1,618 kcal/day after rounding.
With the same age, weight and height, selecting the female coefficient gives 1,451.5 kcal/day, displayed as 1,452 kcal/day. These examples show how the calculator works; they are not recommended daily food intakes.
Resting calories and total daily energy needs
A resting-calorie estimate does not include all the energy used during a day. An activity-based estimate, such as a daily calorie estimate, considers additional activity assumptions. Check which type of result you are comparing when using different tools.
Treat this calculator as an adult information tool. It does not account for medical conditions, pregnancy, breastfeeding or individual treatment needs. For a personal nutrition or weight-management plan, discuss your circumstances with a qualified health professional. The NIDDK resource below provides further information about planning calorie intake and physical activity.
Frequently asked questions
What unit is used for the result?
The result is shown in kcal/day, meaning kilocalories per day. In everyday food and exercise discussions, a kilocalorie is often called a calorie.
Is this a measured metabolic rate?
No. This page estimates resting energy use from the values you enter and the selected equation coefficient. It does not perform a metabolic test.
Why do the two coefficient options give different results?
They use different constants in the same equation: +5 or −161. Keep the other values unchanged to compare how that choice affects the calculation.
Should I use this result as my daily food target?
No. This is a resting estimate, not a complete daily calorie target. It does not include all activity or individual nutrition needs.
Why does another calculator show a different number?
Check whether it uses the same equation, units, age, height, weight and coefficient. Some calculators also apply an activity multiplier or round results differently.
Can I edit the result by changing my inputs?
Yes. Change the input values and run the tool again. Review the new result and its inputs together before keeping a copy.