Basal Metabolic Rate Calculator

What is BMR?

The Basal Metabolic Rate, or BMR, represent the amount of calories your muscles burn every day just to maintain vital operations such as thinking or breathing.

BMR is the amount of calories your body would burn if you were to stay in bed, in a neutrally temperature environment, in the post-absorptive state, the whole day and do nothing at all.


Your Basal Metabolic Rate is the sum of the following processes: blood flow, nervous shims, respiration, maintaining body temperature, heart, lungs, liver, muscles, making new blood cells, hormones, etc...

For the BMR, most of the energy is consumed in maintaining fluid levels in tissues through osmoregulation, and only about 10% is consumed for mechanical work, such as heartbeat, digestion, and breathing.

Your BMR does not include the calories you burn from normal daily activities or exercise.

BMR changes as you age

The Basal Metabolic Rate decreases with age. After the age of 20, it reduces about 2% every decade. This is why many people can’t understand why they gain weight as they get older, but they still have the lifestyle the same way they did in their 20’s or 30’s. They need to reset their BMR to reflect the changes that are taking pease in their bodies.

BMR changes as you age

BMR is the largest factor in determining overall metabolic rate and how many calories you need to gain, maintain or lose weight.

If you are trying to lose weight, a common mistake is to reduce calorie intake drastically. You can choose a highly restrictive diet and decrease your calories by a significant amount. This does the exact opposite of what you would expect. Instead of increasing your BMR, your body goes into starvation mode and your metabolism slows down. In turn, this decreases your BMR by 20%-30%.

Women have naturally a lower BMR than men, as men usually have a lower percentage of body fat and a higher percentage of muscle. By having a lower body fat percentage and a higher percentage of lean muscle mass, a man requires a higher metabolism to maintain that muscle.

How calculate your BMR

The BMR is determined by age, gender, height and weight, as well as individual genetic factors.

To calculate your basal metabolic rate you will need your weight measurements in pounds, your height in inches, and your age in years.

Whether your goal is to lose weight (body fat), gain weight (lean muscle), or to just maintain your current weight, calculating and knowing your BMR can help attain and maintain your goals.

The Harris-Benedict equation has been the standard for decades and is still the most widely used for estimating the basal metabolic rate. You can manually calculate your BMR with the BMR formula.

Or if you want to avoid calculations, you can use our BMR calculator to get the number of calories burned while resting, and the calories you need to gain, maintain or lose weight:

Calculate your Total Calorie Needs

Even the most inactive individual will burn additional calories over their Basal Metabolic Rate by just doing normal functions like smiling. Once you have calculated your BMR, to find out your total daily calorie needs (or TDEE - total daily energy expenditure), you need to multiply your BMR by the activity factor that is appropriate for your lifestyle as indicated in the following table:



Little or no exercise in all day


Lightly Active

Lightly Active

Easy exercise 1-3 days/week


Moderately Active

Moderately Active

Moderate exercise 3-5 days/weeks


Very Active

Very Active

Hard exercise 6-7 days/week


Extremely Active

Extremely Active

Very hard exercise and physical job


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