BMR Calculator - Calculate Your Basal Metabolic Rate
Estimate resting energy expenditure with the Mifflin–St Jeor equation from age, sex, weight, and height. Actual energy use can vary.
What Is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to maintain basic life functions like breathing, blood circulation, and cell production. It accounts for approximately 60–75% of your total daily energy expenditure. Understanding your BMR is fundamental to effective weight management and nutrition planning.
How to Use the BMR Calculator
- Enter your age — Type your current age in years.
- Select your sex — Choose Male or Female from the dropdown.
- Enter your weight — Type your weight in kilograms.
- Enter your height — Type your height in centimeters.
- Click "Calculate BMR" — The tool shows your BMR in kcal/day.
How BMR Is Calculated
This calculator uses the Mifflin-St Jeor equation, a widely used BMR estimation equation:
- Male: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
- Female: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161
BMR Reference Table
| Age | Male BMR (kcal/day) | Female BMR (kcal/day) |
|---|---|---|
| 18–30 | 1,800 – 2,200 | 1,400 – 1,800 |
| 30–50 | 1,700 – 2,100 | 1,300 – 1,700 |
| 50+ | 1,500 – 1,900 | 1,100 – 1,500 |
Using Your BMR
- What this result is: An estimate of calories burned at rest from the age, sex, weight, and height you entered — not a personalized calorie target or diet plan.
- TDEE is separate: Total daily energy expenditure also depends on activity and is not calculated on this page.
- Weight change: Energy balance is often discussed relative to TDEE, not BMR alone. This tool does not provide medical or weight-loss advice.
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is the number of calories your body burns at complete rest — just to stay alive. TDEE (Total Daily Energy Expenditure) includes BMR plus all the calories you burn through daily activities, exercise, and digestion. For most people, TDEE is 1.2 to 1.9 times their BMR, depending on activity level.
How accurate is the Mifflin-St Jeor BMR formula?
The Mifflin–St Jeor equation is a widely used estimate from age, sex, weight, and height. Individual results can differ. This page does not perform a lab measurement such as indirect calorimetry.
Is this BMR result a calorie target for weight change?
No. This calculator estimates resting energy expenditure from the age, sex, weight, and height you enter. It is not a calorie target. Weight change depends on total daily energy use (TDEE), which includes activity and is not calculated here.
Does muscle mass affect BMR?
The Mifflin–St Jeor estimate on this page does not include muscle mass. Two people with the same inputs can still differ in real resting energy use. This tool cannot show that difference.
Does this BMR result tell me how many calories to eat?
This page estimates BMR only. Meal planning is often discussed in terms of TDEE (BMR plus activity), which this calculator does not compute. BMR is not a complete calorie target.
Why is my BMR different from my friend's?
BMR varies based on age, sex, weight, height, muscle mass, genetics, and even hormone levels. Two people of the same age and weight can have very different BMRs. This calculator only applies the Mifflin-St Jeor estimate to the values you enter; it is not personalized medical advice.