BMR Calculator
Estimate how many calories your body burns at rest before adding daily activity.
Simple, fast and clear
Enter your values, review the result, and read the formula used so the calculation is easy to understand.
BMR Calculator
Use the fields below to calculate your result instantly.
What is the BMR Calculator?
A BMR calculator estimates basal metabolic rate, which is the number of calories your body may burn at rest for basic functions such as breathing, circulation and maintaining body temperature. It is a useful starting point for nutrition and fitness planning.
BMR is not the same as total daily calorie need. Your actual daily energy use also depends on activity level, exercise, job type, walking, digestion and other lifestyle factors. That is why BMR is often combined with an activity multiplier to estimate daily calories.
This calculator uses common inputs such as age, gender, height and weight. The result should be treated as an estimate, because metabolism varies from person to person.
How we calculate the result
Formula: BMR is estimated from weight, height, age and gender using the Mifflin St Jeor method
The Mifflin St Jeor method uses body weight, height and age because larger bodies generally require more energy at rest, while BMR often decreases with age. Gender adjustment is included because average body composition differs between groups.
After BMR is calculated, you can multiply it by an activity factor to estimate total daily energy expenditure. This helps compare maintenance, weight-loss and weight-gain calorie targets.
When to use this calculator
Use this calculator to understand resting calorie needs, compare calorie plans and build a starting point for fitness or nutrition goals.
Input tips for better results
Use current weight, height, age and sex selection carefully. BMR formulas estimate resting calorie burn, so do not enter workout calories or daily activity in the base fields.
Compare BMR with calorie needs at different activity levels. The gap between resting burn and active-day calories is important for diet planning.
Limitations of this calculator
This BMR Calculator is an educational estimate. It cannot replace official records, professional advice, medical advice, accounting documents, tax filings, lender statements or employer payroll records.
Real-world health example
Use BMR Calculator as a screening or planning number, then compare it with other signals such as energy level, body measurements, training history and professional advice. Health calculators are useful for awareness, but they do not understand every body type or medical situation.
Mistakes to avoid
Do not treat one calculator result as a diagnosis. Enter the correct units, avoid rounded guesses where possible and review unusual results with a qualified professional.
Frequently Asked Questions
Is BMR my daily calorie target?
Not by itself. BMR estimates resting calories, while daily calorie needs include activity.
Why does age affect BMR?
BMR often changes with age because body composition and metabolic demand can change.
Can two people with the same weight have different BMR?
Yes. Height, age, sex, muscle mass and individual metabolism can all affect BMR.
Helpful tips
- Use current weight, height, age and sex selection carefully. BMR formulas estimate resting calorie burn, so do not enter workout calories or daily activity in the base fields.
- Compare BMR with calorie needs at different activity levels. The gap between resting burn and active-day calories is important for diet planning.
- Do not eat exactly at BMR unless advised. Daily calorie needs are usually higher than resting burn.
- BMR formulas cannot know muscle mass, hormone conditions, medication, illness or individual metabolism.
Before you rely on the result
BMR formulas cannot know muscle mass, hormone conditions, medication, illness or individual metabolism. Keep the input values with the result so you can review the assumption later.