BMR Calculator
Estimate your basal metabolic rate — the calories your body burns at complete rest — using the Mifflin-St Jeor equation.
Reviewed October 7, 2026 Runs in your browser — inputs are never stored
This tool provides general educational estimates only and is not medical advice. It does not diagnose, treat, or replace guidance from a qualified healthcare provider. Consult a doctor for decisions about your health.
About the BMR Calculator
The BMR calculator estimates your basal metabolic rate — the calories your body burns at complete rest to keep you alive: breathing, circulation, temperature control and cell repair. BMR usually accounts for 60–70% of the calories a typical adult uses each day. The tool uses the Mifflin-St Jeor equation, which research has found to be the most accurate of the common predictive equations for healthy adults. It needs only your sex, age, height and weight. BMR is the starting point for working out daily calorie needs: multiply it by an activity factor and you get your total daily energy expenditure (TDEE).
How to use it
- 1Choose metric or imperial units.
- 2Select your sex.
- 3Enter your age, height and current weight.
- 4Press Calculate to see your BMR in calories per day.
- 5Use the TDEE or calorie calculator to add your activity level.
Worked example
a 30-year-old man who is 175 cm tall and weighs 70 kg has a BMR of 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,649 kcal a day. A 30-year-old woman who is 165 cm and 60 kg has a BMR of about 1,320 kcal a day.
How it works
Formula (Mifflin-St Jeor)
Men: 10·kg + 6.25·cm − 5·age + 5
Women: 10·kg + 6.25·cm − 5·age − 161
Who it is for
People planning a diet, athletes estimating energy needs, and anyone curious about how many calories their body uses at rest.
Why it helps
Every calorie target starts from BMR, so an accurate estimate makes the rest of a nutrition plan more reliable.
Common use cases
- Setting a baseline before calculating daily calorie needs
- Seeing how BMR changes as you lose or gain weight
- Comparing your estimate with a lab measurement
Common mistakes to avoid
- Eating at BMR level to lose weight — BMR excludes all daily activity, so it is far below what you actually burn.
- Expecting an equation to fit very muscular or very lean people as well as it fits average adults.
Frequently asked questions
A:The number of calories your body needs to maintain basic functions like breathing and circulation while at rest.
A:TDEE (total daily energy expenditure) is BMR multiplied by an activity factor to account for movement and exercise.
Reviewed for accuracy · Last updated October 7, 2026
Formulas follow recognised clinical references — including WHO BMI classifications, the Mifflin-St Jeor equation, and Naegele’s rule — and are periodically checked against published reference values.
CalcWisee Editorial Team
Calculator development and formula review
CalcWisee is an independent site founded by Ayman. Every calculator is built from a published formula or official definition, tested against hand-worked examples before it goes live, and corrected promptly when a reader reports an issue to ayman@calcwisee.com.
Expertise: Financial mathematics, Health and fitness formulas, Applied mathematics, Unit conversion standards
References & sources
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