BMR Calculator

Estimate energy used at rest from age, height, weight and equation settings. Enter your own values below to see estimated basal metabolic rate and check the method behind it.

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Your inputs

Change the example values to match your situation.

Your result

Let’s work it out.

Fill in your inputs and select Calculate.
Your result and breakdown will appear here.

How this calculator works

Mifflin–St Jeor: BMR = 10 × kg + 6.25 × cm − 5 × age + 5 (male) or −161 (female).

Before you use the result

  • Estimates for general information. They do not diagnose a condition or replace a qualified clinician’s assessment.

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What is BMR Calculator?

BMR Calculator helps you estimate energy used at rest from age, height, weight and equation settings.

The main result is estimated basal metabolic rate. The formula, example and assumptions below explain how to interpret it.

How to use BMR Calculator

Use the example to get familiar with the form, then enter your own figures. Any rates in the example are illustrative. Check the field labels and units before calculating.

  1. Gather weight (kg), height (cm), age and sex used by the formula. Use values from the same situation or reporting period.
  2. Replace the example weight with your own value, then complete the other fields. Check the displayed units and each selected option.
  3. Select Calculate and read estimated basal metabolic rate. Change one input and calculate again to compare a second scenario. Reset restores the original example.
  • Enter weight in kg, at least 20 and at most 500. Decimals are accepted.
  • Enter height in cm, at least 100 and at most 250. Decimals are accepted.
  • Enter age, at least 18 and at most 100. Use a whole number.
  • Choose sex used by the formula from Male and Female.

BMR Calculator: a worked example

With the inputs below, the result is 1,617.5 kcal/day (estimated basal metabolic rate). Follow the example, then replace these illustrative values with your own.

Example inputs and output
Input or outputExample value
Weight (kg)70 kg
Height (cm)170 cm
Age30
Sex used by the formulaMale
Estimated basal metabolic rate1,617.5 kcal/day

Understanding the BMR result

The main output is estimated basal metabolic rate, expressed in kcal/day. It applies to the inputs and operation you selected.

Displayed results use a readable number of decimal places. When checking a result by hand, keep extra precision until the last step. To compare scenarios, change one input at a time and keep the others fixed.

BMR Calculator: assumptions and common mistakes

A useful estimate starts with the right inputs. Check the following assumptions and limits before applying the result to your situation.

  • Estimates for general information. They do not diagnose a condition or replace a qualified clinician’s assessment.
  • Health estimates are context-dependent. Age, pregnancy, illness, medication and individual measurements can affect interpretation; these tools do not diagnose a condition.

For wider guidance, visit World Health Organization. The formula and scope of this specific tool are stated on this page.

BMR Calculator FAQs

What does BMR Calculator calculate?

BMR Calculator helps you estimate energy used at rest from age, height, weight and equation settings. Its main output is estimated basal metabolic rate in kcal/day.

What inputs do I need for BMR Calculator?

You need weight (kg), height (cm), age and sex used by the formula. Use the field labels and units to match your figures to the formula.

Which formula does BMR Calculator use?

Mifflin–St Jeor: BMR = 10 × kg + 6.25 × cm − 5 × age + 5 (male) or −161 (female).

What is a worked example for BMR Calculator?

Example inputs: Weight: 70 kg; Height: 170 cm; Age: 30; Sex used by the formula: Male. The result is 1,617.5 kcal/day (estimated basal metabolic rate).

How should I enter weight?

Enter weight in kg, at least 20 and at most 500. Decimals are accepted.

How do I choose sex used by the formula?

Choose sex used by the formula from Male and Female. The example uses Male; replace it if your circumstances differ.

How should I read estimated basal metabolic rate?

The main output is estimated basal metabolic rate, expressed in kcal/day. It applies to the inputs and operation you selected.

Why might my BMR Calculator result differ from my records?

Estimates for general information. They do not diagnose a condition or replace a qualified clinician’s assessment. Differences in entered values, units or rounding can also change the comparison.

Can I compare two scenarios in BMR Calculator?

Yes. Note your first estimated basal metabolic rate, change weight or another input, and select Calculate again. Editing a field clears the old result so it is not mistaken for a new calculation.

Is BMR Calculator free, and where are my inputs calculated?

This calculator is free to use without signing in. Its formula runs in your browser; calculator inputs are not sent to a calculation API. The inputs reset to the example values when you reset the form or start a fresh page.