BMR Calculator: Our Best, Most Accurate BMR Calculator [Free] (2024)

We think this is our best BMR Calculator ever. It may be the most accurate BMR Calculator with body fat online. It's designed to help you work out how many calories your body burns to maintain life, which includes all the basic bodily functions. It does not account for sleeping, moving, eating, exercising, and other activties you do. It's just the most basic level of life.

Try our Accurate TDEE Calculator to get your Total Daily Energy Expenditure.

Atlas Says: BMR is a great calculation when working out a minimum number of calories your body needs which is ideal for your fitness and nutrition plan. Never eat fewer calories than your BMR as it's the minimum for a healthy functioning body.

BMR vs TDEE?

Your BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure), differ slightly in that your TDEE calculation is your BMR plus all of your daily activities including sleeping, walking, working, exercising, eating, etc.

Atlas Says: Try our TDEE Calculator to discover how many calories you burn in a day.

What formulas do you use to work out BMR?

There are two formula's we use in this accurare Basal Metabolic Calculator, they are: Mifflin-St Jeor and Katch-McArdle. If you include body fat percentage then the calculator uses the accurate Katch-McArdle formula. However, if you do not add your body fat percentage, then the calculator falls back to using the Mifflin-St Jeor formula (which is still very accurate). This formula excludes the activity level factor usually included in the above formulas to provide an accurate BMR calculation.

Mifflin-St Jeor Formula

Male = ( 10 x Weight in KGs ) + ( 6.25 x Height in CMs ) - ( 5 x Age ) + 5
Female = ( 10 x Weight in KGs ) + ( 6.25 x Height in CMs ) - ( 5 x Age ) - 161

Katch-McArdle Formula

Male & Female = 370 + ( 21.6 x ( Weight in KGs - (Body Fat % x Weight in KGs) ) )

Atlas Says: These formulas give an estimation of the number of calories your body burns staying alive. It's best to say that there is a margin of error of 10%, so regularly check and tweak to provide better results.

BMR Calculations and why calculating BMR is important

The single most important reason for calculating BMR is to do with accurately estimating how many calories your body requires depending on your own personal body composition - with the exclusion of your daily active levels.

Once you have this number, then you can use it as the backbone for your training and nutrition goals when you factor in your daily activity levels.

Calculating BMR for fat loss. If you are trying to reduce the amount of body fat then you will require a deficit against your BMR calculation. For the example of calculating BMR for fat loss, if your BMR is 2000 calories + daily activity level calories of 500, then a 10% calorie deficit will mean that you need to roughly eat 2250 calories a day to ensure you are in caloric deficit. The 10% deficit used here is a manageable deficit, a deficit of between 10% to 20% is recommended for reducing body fat - too many calories will also mean muscle loss.

Calculating BMR for muscle gain. Conversly if you are trying to gain muscle then you will require a calorie surplus against your BMR calculation. For the example of calculating BMR for muscle gain, if your BMR is 2000 calories + daily activity level calories of 500, then a 10% calorie surplus will mean that you need to roughly eat 2750 calories a day to ensure you are in caloric surplus. The 10% surplus used here is a manageable surplus, a surplus of between 10% to 20% is recommended for muscle gain- too many calories will also mean fat gain.

Please also note that these BMR calcualtion examples are when combining nutrition with resistance and cardio training for maximum benefit + don't forget your BMR does not include the calories you burn through your daily activity.

Atlas Says: BMR calulations are the backbone for fat loss, muscle gain, and weight maintenance. What is measured, can be improved.

Why should you use our best, most accurate BMR Calculator for free?

We have been working hard to bring you our best, most accurate BMR Calculator in this latest version of Atlas. Cue the sales pitch...but it's free.

It's really important that our BMR Calculator is not just accurate but also better than any other on the entire web. We may just have done exactly that!

Below are some great reasons we think you should use our BMR Calculator over any of those other inferior calculators online.

100% Completely Free - You heard it right, our BMR Calculator is completely free to use now and forever.

Absolutely No Sign Up Forms - We don't want your data. Not your email address, not your name, address, or even your credit card details.

Instant Online Body Insights - Unlike some of the other fitness calculators we show your results instantly online. Get instant access to your BMR Calculator results.

Accurate BMR Calculator - Because we think this is our best BMR Calculator it has to be super accurate, so we did just that and made it so.

Privacy Friendly - As we don't ask you to sign up or for any of your personal details, our tool is privacy friendly.