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Resting Energy Expenditure Screening Utility

BMR Calculator

Estimate your basal metabolic rate (BMR): the energy your body uses at rest for essential functions. This calculator uses age, height, weight, and sex used by the equation to provide an informational estimate.

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Calculate My BMRPrivate by default • Metric and imperial units • Adults & Teens aged 15+ • Informational only

Calculate Your Basal Metabolic Rate

Basal Metabolic Rate (BMR) represents the minimum baseline energy expenditure your body requires to maintain vital biological functions while at complete rest. Understanding your BMR provides insight into your resting energy expenditure before accounting for daily movement or exercise.

Basal Metabolic Rate (BMR) Settings

Resting Energy Expenditure Estimator (Adults & Teens 15+)

Designed for adults and older teens aged 15 and over.

The standard equation uses separate reference values. It cannot account for every body or health circumstance.

Private by default • Metric and imperial units • Adults & Teens aged 15+ • Informational only

Basal Metabolic Rate (BMR) Result

Method: Mifflin–St Jeor Equation
Estimated Calories Used at Rest
1,370 calories/day

This represents an estimate of the energy your body uses at rest for basic physiological functions such as breathing, blood circulation, and cell production.

Your estimated BMR is 1,370 calories per day. This represents an estimate of the energy your body uses at rest for basic functions. Your actual daily calorie needs are usually higher because they also include movement, exercise, and digestion.

Formula Applied (Mifflin–St Jeor):
BMR = (10 × 65 kg) + (6.25 × 165 cm) − (5 × 30) − 161 = 1370 calories/day
Inputs: Age 30 • Female • Height 165 cm • Weight 65 kg
Want to estimate your total daily energy needs (TDEE)?

BMR covers energy used at rest. Daily calorie needs also include exercise and movement.

Go to Calorie Calculator
Calculations are processed locally in your browser. Inputs and BMR values are private and not stored.

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Important BMR Limitations

BMR is an estimate, not a direct metabolic measurement. It can vary with body composition, genetics, illness, medications, hormonal changes, sleep, pregnancy, breastfeeding, and recent activity. Daily calorie needs are higher than BMR and also depend on movement, exercise, and digestion.

Last medically reviewed by Medical & Assessment Content Team (Dr. Faisal Saddique, MD)
Last reviewed: August 2026

BMR Calculator for Metric and Imperial Units

This calculator supports both metric (kilograms and centimeters) and imperial (pounds, feet, and inches) measurements. Switching unit toggles preserves exact numerical equivalency so you can easily calculate your BMR in whichever unit format you prefer.

What Is Basal Metabolic Rate?

Basal Metabolic Rate is the number of calories your body burns at rest to perform essential life-sustaining functions such as respiration, blood circulation, cellular repair, body temperature maintenance, and brain function. It accounts for approximately 60% to 75% of total daily energy expenditure in most sedentary adults.

How Is BMR Calculated?

This calculator uses the validated Mifflin–St Jeor equation, widely recognized in clinical nutrition for its reliability across adult populations:

Mifflin–St Jeor Formula for Men

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5

Calculates resting energy expenditure for men in calories per day.

Mifflin–St Jeor Formula for Women

BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

Calculates resting energy expenditure for women in calories per day.

BMR vs. TDEE: What Is the Difference?

BMR is not the same as daily calorie needs.

  • BMR (Basal Metabolic Rate): Energy used strictly at rest for basic physiological survival.
  • TDEE (Total Daily Energy Expenditure): Energy used across a full day, combining BMR with physical activity, exercise, and the thermic effect of food digestion.

To estimate your total daily calorie needs including activity, visit our Calorie Calculator.

What Can Affect BMR?

Several physiological factors influence resting metabolic rate:

  • Muscle Mass: Lean muscle tissue is more metabolically active than fat tissue at rest.
  • Age: BMR naturally decreases gradually with age due to muscle mass changes.
  • Genetics & Hormones: Thyroid hormone levels and genetic variations alter metabolic speed.
  • Illness & Recovery: Fever, infection, and surgical recovery elevate resting energy expenditure.

Limitations of BMR Calculators

BMR is an estimate, not a direct metabolic measurement. It can vary with body composition, genetics, illness, medications, hormonal changes, sleep, pregnancy, breastfeeding, and recent activity. Daily calorie needs are higher than BMR and also depend on movement, exercise, and digestion.

Using BMR Estimates Safely

BMR estimates should not be used as a stand-alone calorie prescription. If you are pregnant, breastfeeding, under 15, managing an eating disorder, recovering from illness or surgery, or have a medical condition that affects energy needs, seek guidance from a qualified healthcare professional.

Public Health Sources & Citations

  • Mifflin, M. D., et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition.
  • Academy of Nutrition and Dietetics. Metabolic Rate and Resting Energy Expenditure Reference Values. Available at: eatright.org

Frequently Asked Questions

BMR, or basal metabolic rate, estimates the energy your body uses at rest for essential functions such as breathing, circulation, and temperature regulation.
No. BMR is an estimate of energy used at rest. Daily calorie needs also include movement, exercise, and digestion.
This calculator uses the Mifflin–St Jeor equation, which estimates BMR from age, height, weight, and sex used by the equation.
BMR estimates energy use at rest. TDEE, or total daily energy expenditure, estimates energy used across a full day, including activity and digestion.
It can provide a useful estimate for many adults, but it cannot account for every factor that affects metabolism or individual energy needs.
Your body uses energy beyond resting functions through everyday movement, exercise, digestion, and other normal processes.
This calculator is designed for adults and older teens aged 15 and above. Children and teenagers under 15 should use age-appropriate guidance from a qualified healthcare professional.
No. Pregnancy and breastfeeding change energy needs. Discuss relevant nutrition questions with a qualified healthcare professional.
No. Calculations run locally in the browser. Inputs should not be saved, shared, or used for advertising.
Verified Community Feedback

What people are saying

Real user ratings and reviews for BMR Calculator.

5.0
1 Verified Review
Carlos Mendez
3 months ago

Comparing Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle side-by-side gave me the exact baseline I needed.

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