BMR Calculator

The BMR calculator allows you to calculate your Basal Metabolic Rate (BMR) as well as other information relating to the calories you burn a day.  To use the calculator, simply input details about yourself such as you age, gender, weight and height.  The calculator will then calculate an estimate of your BMR and adjust you BMR by various factors to allow you to see an estimate of the calories you burn a day based on your level of activity.

Your Basal Metabolic Rate is defined on Wikipedia as:

“the amount of energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of fasting in humans)”

You are basically looking at the calories you burn a day when at rest with no digestion occurring.  There are various methods to calculate an estimate of your BMR and the calculator will return two estimates based on the formulas developed by MD Mifflin and ST St Jeor as well as the Harris-Benedict equation.  These equations allow an approximation of your BMR to be computed from the above data.

The equation introduced by MD Miffin and ST St Jeor is as follows:

BMR = (9.99 x weight + 6.25 x height – 4.92 x age + s ) kcal/day

Here, weight is in Kilograms, height is in centimeters and age is in years.  s is a factor to adjust for gender and adopts the value +5 for males and -161 for females.

As an alternative method of calculation,  the Harris Benedict equations adopt separate equations for men and women as follows:

For Men:

BMR = (13.7516 x weight + 5.0033 x height – 6.755 x age + 66.473) kcal/day

For Women:

BMR = (9.5634 x weight + 1.8496 x height – 4.6756 x age + 655.0955) kcal/day

Similarly to the above formula by MD Miffin and ST St Jeor, weight is in Kilograms, height is in centimeters and age is in years.

Some studies have shown the equation by MD Miffin and ST St Jeor to be more accurate here, while the Harris Benedict equation was created in 1919 and has historical significance.

The calculator will return an estimate of your BMR using both of these methods.

One of the useful properties of computing such an estimate of your BMR is that you can then use this to esitimate the calories you burn a day.  The BMR calculator will then adjust your BMR by various factors to show estimates of the calories you burn a day based on your activity level.

These estimates are simply computed by multiplying your BMR by the factor specific to an activity level.  The activity levels and their factors are as follows:

Activity Level	Description	Formula
Low	You get little to no exercise	Calories Burned a Day = BMR x 1.2
Light	You exercise lightly (1-3 days per week)	Calories Burned a Day = BMR x 1.375
Moderate	You exercise moderately (3-5 days per week)	Calories Burned a Day = BMR x 1.55
High	You exercise heavily (6-7 days per week)	Calories Burned a Day = BMR x 1.725
Very High	You exercise very heavily (i.e. 2x per day, extra heavy workouts)	Calories Burned a Day = BMR x 1.9

You might also like to take a look at our more general weight loss calculator. This calculator calculates some additional pieces of weight loss information such as your BMI and recommendations on the number of calories you should consume.

A lot of the research for this calculator was based on the Wikipedia entries relating to Basal Metabolic Rate and the Harris Benedict Equation.

Disclaimer:  This tool is provided for informational purposes only.  The equations applied here are general equations that generalize between people and as such may not be accurate in all cases.  The tool is not relevant to children or pregnant women. This calculator is provided free of charge.  No guarantee of the accuracy of this tool or its suitability to all people is provided. Before commencing a weight loss program, always consult your doctor.