Basal Metabolic Rate (BMR) Calculator

By | February 11, 2004

This basal metabolic rate (BMR) calculator shows you your BMR numbers, but this comprehensive article also shares the inside scoop on what it means and why you should care.

BMR Calculator

Enter your age, weight, body fat percentage, and height to determine your BMR.

Enter weight:
Enter your body fat as a decimal (22% = 22.0):
Enter your height in inches:
Enter your age in years:
Lean mass:
BMR (formula 1):

12.7 * height + 66 + 6.3 * lean – 6.8 * age
BMR (formula 2):):

( 13.8 * lean ) / 2.2 + 5 * 2.54 * height – 6.8 * age + 66.5
BMR (formula 1):):

4.7 * height + 655 + 4.3 * lean – 4.7 * age
BMR (formula 2):):

( 9.6 * lean ) / 2.2 + 1.8 * 2.54 * height – 4.7 * age + 655.1

What is Basal Metabolic Rate?

Basal Metabolic Rate (BMR) is a formula that estimates how much energy you expend per day. When you breathe, you expend energy. When your body processes nutrients, this requires energy.

What most people don’t understand about basal metabolic rate, is that this is only an indicator of your most basic functions (hence: "basal"). It does not include walking, talking, sitting, or even thinking hard. In fact, your BMR really only approximates how many calories you would burn in a 24 hour period if you were SLEEPING throughout that period!

Based on Lean Mass

While some equations use total body weight, the two provided here are based on lean mass. If two people weigh the same, but one has low body fat with tons of muscle – but the other has high fat with almost no muscle, who will burn more calories at rest?

The term "tone" refers to the fact that trained muscles constantly contract to prepare themselves for anticipated work. So when the muscles become firm and hard, it is due to mini-contractions taking place constantly (a paralyzed muscle, no matter how large, will become flaccid). These mini-contractions burn a significant amount of calories, even at rest, and this is why it is important to increase lean mass when your goal is the reduction of body fat.

What’s BMR Good For?

So, what do you do with this? NOTHING! Really. The equation here is just an approximation. Some people will even say that you can take it and multiply it, say, by 1.65 and figure out how many calories you will burn if you are "active". This is still just a shot in the dark.

People Have Differing Metabolism

Due to any number of factors, despite having the same amount of lean mass, two people may still have different metabolisms. Ever heard the term "fast metabolism?" – it’s true, some people do have faster metabolisms. And someone deficient in certain nutrients or who has starved themselves on a low calorie diet will have a much lower metabolism than someone who eats the proper amount of nutrient-dense foods. Use this as a guideline only, and understand that you most likely will never consume less calories than this unless you are in some special "cutting" phase for a competition.