Basal Metabolic Rate
you are curious about the math behind this BMR calculation, then be
to read on. If you are looking for the online calculator, click here
With this article you will learn more about your basal
metabolic rate and how it's calculated.
The basal metabolic rate calculation takes into account many different
There are different methods used for the
calculation with the most
common being the
This formula uses height,
age and gender to determine your basal metabolic rate.
results of the Basal Metabolic Rate calculation using these variables
are an estimate,
but will be
fairly accurate for most people.
No one formula will be exact as there are other factors, such as family
traits and frame size that are not taken into account.
Therefore all of the various calculators will be an approximation of
BMR Calculation Explained
There are several variables that are used in the BMR calculation. These
include age, gender, weight and height. These factors are used to
determine your resting BMR.
Additionally the activity level is used to
determine your total daily caloric needs. You
may be wondering why and how these variables are used in the BMR
Well, age plays a role
in your metabolic rate.
As we age, our metabolism slows down.
I know this doesn't
fair to those of us over 40, but it's true. Gender also plays a role in
Why? Well men tend to have more
muscle and the more lean muscle you have the higher your basal
body surface is needed to determine
BMR calculation. This is why both weight and height are used.
body surface you have, the more calories you burn through your basal
However, because lean body mass is
not a variable in the Harris Benedict formula, it may be inaccurate for
muscular as it may underestimate caloric needs. This is
because muscles are more metabolically demanding than fat.
may also be inaccurate for people with an extremely high percentage of
body fat, overestimating their caloric needs as your body uses fewer
calories to sustain the fat.
As stated above, this BMR calculator is using the Harris-Benedict
formula to determine the results. Note that this formula uses kilograms
for weight and centimeters for
height. Below this formula you will see the conversion
factors to use for pounds and inches.
66 + (13.7 x
weight) + (5 x height) - (6.8 x age in years)
to Imperial conversion
Women: 655 + (9.6 x weight) + (1.8 x height) - (4.7 x age in years)
1 inch = 2.54
Example, if you are 5’3” (or 63”), then you height in cm equals 63
inches x 2.54 cm = 160 cm
1 pound = .45 kg (1 kg = 2.2 pounds so 1 pound divided by 2.2 kg equals
Example, if you weight 160 pounds, then your weight in kg equals 160
lbs x .45 kg = 72 kg
So, if you are a 40 year old female weighing 150 pounds at 5’3” (or 63
inches), your calculation would be;
655 + (9.6 x [150 lbs x .45 kg]) + (1.8 x [63 inches x 2.54 cm]) – (4.7
+ (9.6 x 68 kg)
+ (1.8 x 160 cm) – (188)
+ 653 + 288 –
188 = 1408 calories/day
The Activity Factor
will use the results of your basal metabolic
calculation and then factor in an activity level. This will
give you the amount of calories you burn based on the BMR as well as
The reason you need to understand the activity factor for this BMR
calculator, is you want to
ensure you are consuming enough calories for your BMR as well as your
level of exercise. By factoring in the activity level in a
weight loss calculator you will get the proper daily calorie intake
needs to sustain and/or lose weight.
Below is what is used to factor in the activity level.
||no or little exercise
exercise 1 - 3 days/week
exercise/sports 3 - 5 days/week
exercise/sports 6 - 7 days/week
daily exercise/sports plus physical job or exercise 2x a day
If your basal metabolic rate is 1408, then based on your activity
level, your daily
calorie needs to maintain your weight would be as follows;
- Sedentary =
1408 x 1.2 = 1690
- Lightly active = 1408 x 1.375 = 1936
- Moderately active = 1408 x 1.55 = 2182
- Very active = 1408 x 1.725 = 2429
- Extremely active = 1408 x 1.9 = 2675
Now that you understand the BMR Calculation, use the online calculator
to find your Basal Metabolic Rate.
Find out how to calculate your Body Mass Index by reading this article. The BMI is used as a guide to see if you have medical risks due to your
Heart Rate Calculator
Here is another free online calculator you can use to ensure you are
working out within your target heart rate zone.
Give your BMR a boost with these metabolism boosting tips. Find ways to rev up your metabolism will help you burn more calories in