BMR Calculator: Calculate Your Basal MetaboliC
What Is BMR?
Basal Metabolic Rate, or BMR , is an estimate of how many calories your body uses each day to support essential functions while at rest. These functions include breathing, circulation, brain activity, temperature regulation, and normal cellular processes.
Use the BMR Calculator above to estimate your daily resting calorie needs from your age, sex, height, and weight.
How Is BMR Calculated?
This calculator uses the Mifflin-St Jeor equation , a widely used formula for estimating resting energy expenditure.
For men:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
For women:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
For example, a 30-year-old man who weighs 70 kg and is 175 cm tall would have an estimated BMR of about 1,649 calories per day .
The calculator performs this calculation automatically when you enter your details.
What Does Your BMR Result Mean?
Your BMR represents an estimate of the energy your body uses at rest. It is not the same as the total number of calories you burn in a normal day .
Walking, working, exercising, digesting food, and other daily activities all require additional energy.
For example, if your estimated BMR is 1,600 calories, this does not mean 1,600 calories is automatically your daily calorie target. Your actual daily energy expenditure will usually be higher.
To estimate the calories you burn across an entire day, use the TDEE Calculator , which combines your resting energy needs with your activity level.
What Affects Your BMR?
BMR varies from person to person. Important factors include:
- Body size: Larger bodies generally require more energy at rest.
- Age: Energy needs can change as body composition changes with age.
- Sex: The Mifflin-St Jeor equation uses different constants for men and women.
- Body composition: Lean tissue generally uses more energy than fat tissue.
This is why two people of the same age may receive different BMR estimates.
How Accurate Is a BMR Calculator?
A BMR calculator provides an estimate , not a direct measurement of metabolism.
Predictive equations work well as practical starting points, but actual resting energy expenditure can vary because of differences in body composition, genetics, health status, and other individual factors.
Laboratory methods such as indirect calorimetry can measure resting energy expenditure more directly when greater precision is required.
Frequently Asked Questions
What is a normal BMR?
There is no single normal BMR for everyone. Your estimated BMR depends on factors such as your age, sex, height, weight, and body composition.
Is BMR the same as TDEE?
No. BMR estimates the energy your body uses at rest. TDEE estimates your total daily energy expenditure after accounting for physical activity and other daily energy use.
Does BMR include exercise?
No. BMR represents resting energy needs and does not include calories burned through exercise or normal daily activity.
Why does BMR change with age?
BMR can change with age partly because body size and body composition often change over time, including changes in lean muscle mass.
Calculator Methodology
The NutritionSolver BMR Calculator uses the Mifflin-St Jeor equation with age, sex, height, and weight to estimate resting energy needs.
Results are estimates intended for general educational use and should not be treated as a medical diagnosis or an exact measurement of your metabolism.