Body & Fitness

BMR Calculator

Calculate Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula.

By Calculator Suite Pro Editorial Team | Last updated March 18, 2026

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SexWeight (kg)Height (cm)Age (years)

BMR

1699 kcal/day

Formula

Mifflin-St Jeor

Use

Resting calories

Use TDEE for daily needs.

Direct answer

BMR Calculator gives an instant result from your inputs. BMR (Basal Metabolic Rate) estimates how many calories your body burns per day at rest. Think of it as the energy needed for basic functions like breathing, circulation, and temperature regulation. Formula snapshot: Mifflin-St Jeor estimates BMR using weight, height, age, and sex. Example: Sex: Men, Weight: 75kg, Height: 175cm, Age: 30 -> BMR estimate shown in kcal/day.

About this calculator

BMR (Basal Metabolic Rate) estimates how many calories your body burns per day at rest. Think of it as the energy needed for basic functions like breathing, circulation, and temperature regulation.

This calculator uses the Mifflin-St Jeor formula, a commonly used modern equation for estimating BMR in adults.

BMR is only one part of daily energy needs. For a fuller estimate that includes activity, use the TDEE calculator.

How it works

A quick explanation of the logic behind the results, so you can trust what you see.

Mifflin-St Jeor estimates BMR using weight, height, age, and sex.
Men: BMR = 10w + 6.25h - 5a + 5.
Women: BMR = 10w + 6.25h - 5a - 161.
The result is kcal/day, representing energy burned at rest over 24 hours.

Formula used

These are the core formulas and logic rules used by this calculator.

Mifflin-St Jeor estimates BMR using weight, height, age, and sex.
Men: BMR = 10w + 6.25h - 5a + 5.
Women: BMR = 10w + 6.25h - 5a - 161.
The result is kcal/day, representing energy burned at rest over 24 hours.

Common use cases

Below are common real-world scenarios where this calculator is useful.

Estimating resting calorie burn
Setting a starting point for nutrition planning
Comparing calorie needs between individuals
Building a calorie deficit/surplus plan (with TDEE)
Understanding how weight/height/age affect energy needs
Fitness coaching and baseline planning
Education (learning BMR formulas)
Tracking estimated BMR changes over time

How to use

Select sex.
Enter weight (kg), height (cm), and age (years).
Calculate to see BMR in kcal/day.
Use the result as an estimate, not an exact lab measurement.
Open TDEE calculator to include activity level.

Common mistakes to avoid

These are the issues that most often cause confusing results.

Confusing BMR with TDEE (BMR does not include activity).
Entering height in meters instead of centimeters.
Using BMR as a guaranteed calorie target (it is an estimate).
Ignoring that body composition can affect real metabolism.
Using the formula for children/teens without proper guidance.

Tips and notes

Use BMR as a baseline, then use TDEE for daily maintenance calories.
If your goal is weight change, adjust from TDEE, not from BMR.
Track trends: if your weight changes, your BMR estimate will change too.
Pair with Macro Calculator to convert calories into macro targets.
For medical conditions, consult a qualified professional before changing diet.

Glossary

Quick definitions for common terms used in this calculator.

BMR

Basal Metabolic Rate: estimated calories burned per day at rest.

kcal/day

Kilocalories per day, a unit of daily energy use.

Examples

Typical adult example

Input: Sex: Men, Weight: 75kg, Height: 175cm, Age: 30

Output: BMR estimate shown in kcal/day

Another example

Input: Sex: Women, Weight: 60kg, Height: 165cm, Age: 28

Output: BMR estimate shown in kcal/day

Weight change impact

Input: Increase weight by 5kg

Output: BMR estimate increases

FAQ

What is the difference between BMR and TDEE?

BMR is calories burned at rest. TDEE includes activity and represents daily maintenance calories.

Is Mifflin-St Jeor accurate?

It is a widely used estimate for adults, but individuals vary. Lab tests can differ from formula estimates.

Does muscle mass affect BMR?

Yes. More lean mass often increases energy needs, which is why BMR is an estimate.

Can I use BMR to lose weight?

Use TDEE for daily targets, then create a reasonable deficit or surplus based on goals.

Why is sex required?

The formula uses a sex-specific constant for typical body composition differences.

Is BMR the same as resting metabolic rate (RMR)?

They are related. RMR is similar but measured under less strict conditions. In practice, people use them interchangeably.

Is this calculator free to use?

Yes. This calculator is free to use without signup.

Can I use this calculator on mobile?

Yes. The calculator is mobile-friendly and works on desktop as well.

Last updated and references

Last updated: March 18, 2026

Reviewed by Calculator Suite Pro Editorial Team.

For sensitive health and finance topics, review official sources in addition to calculator outputs.

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