Basal metabolic rate (BMR) is the amount of energy your body expends at rest just to keep your vital organ systems and metabolic processes functioning. When you are active, your metabolic rate increases to provide the extra energy you need. Use our online calculator to determine your BMR.
How to Use the Widget
Instead of working with a BMR formula, use our online calculator to make it easier to compute your number. To use the calculator above:
- Select whether you'd like to use US Customary units or metric units.
- Select whether you identify as male or female.
- Choose your activity level, from sedentary to extremely active.
- Enter your age, weight and height in the appropriate boxes.
- Click "Calculate."
- The widget will then display your BMR, as well as the number of daily calories you need to consume to maintain your current weight at your current activity level.
- Click "Clear Results" to perform a new calculation.
The Basal Metabolic Rate
Your basal metabolic rate is the baseline rate at which your body burns your sources of fuel to provide sufficient energy to maintain your vital functions at rest, including:
- Pumping of your heart
- Brain and peripheral nerves activities
- Maintaining your muscles, digestive system, liver, urinary system, skin and other endocrine systems
- Physiological functions, such as processing carbohydrates, protein and fat
Your BMR is the minimum energy your body utilizes to keep you alive in a warm, resting state. When you start moving, your metabolism increases to match your new caloric (energy) needs.
Calculating the BMR
The BMR calculation takes into account your height, weight, age and gender. Men tend to have a higher BMR than women and BMR decreases with age because you use less energy for basal functions.
The formulae for calculating BMR multiplies each of the parameters by various factors based on your gender. The multiplication factors for weight and height are different depending on the system of measurements you use, but the factor for age remains the same.
Imperial System of Measurement
- Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
- Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)
Using the Metric System
- Women: BMR = 655 + (9.6 x weight in kilos) + (1.8 x height in cm) - (4.7 x age in years)
- Men: BMR = 66 + (13.7 x weight in kilos) + (5 x height in cm) - (6.8 x age in years)
Converting BMR to Your Calorie Needs
The Harris Benedict Equation allows you to convert your BMR to the number of calories you need to consume daily based on your level of activity. You multiply your BMR with a conversion factor for one of five levels of activity, from little or none to vigorous exercise and sports.
Using Your BMR Results
Your BMR and conversion using the Harris Benedict Equation gives you the number of calories you typically use each day at your given activity level. To maintain your weight, eat only that many calories. Eat fewer calories if you want to lose weight and more if you want to gain.
Note that the BMR calculations do not factor for lean body mass. The more muscular you are, the higher your BMR and the more calories you expend, because lean muscle burns more energy than fat. If you are muscular, you use more energy than your obese friend of equal weight, even at rest.
Simplify Your Calculation
Instead of using complicated formulae, simplify your BMR calculation by using our digital calculator. Use the conversion to calories to help you manage and maintain a healthy weight.