BMI Calculator

Get to know your BMI plus your calorie requirements, macros, tdee, bmr, rmr, ideal weight, mmp, and much more all in one


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Accurate BMI Calculator


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Accurate BMI Calculator

We think this is our best BMI Calculator ever. It may be the most accurate BMI Calculator online. It's designed to work out what your Body Mass Index is. Body Mass Index is a rule of thumb calculation that helps medical professionals in quickly working out if someone is classed as underweight, normal weight, overweight, or obese.

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

Atlas Says: The BMI calculation is applicable more to medical and public health professionals seeing trends in large populations, rather than a tool for individuals to work out if they are classed as a 'healthy' body shape.

How do you calculate BMI?

The BMI (Body Mass Index) calculation is pretty simple. You divided the body mass (kg) by the square of the body height (m). The result is your BMI with the units of kg/m2, resulting from mass in kilograms and height in metres.

Metric BMI Formula

BMI = kg / m2
(mass in kg divided by height in metres squared)

Imperial BMI Formula

BMI = (lbs x 703) / in2
(mass in lbs mutiplied by 703 divided by height in inches squared)

What does BMI work out?

BMI helps to categories your body mass in to 4 commonly used ranges which are underweight: under 18.5, normal weight: 18.5 to 25, overweight: 25 to 30, obese: over 30.

Atlas Says: The BMI calculate has it's limitations, including, if you are tall or have a higher than average muscle mass.

What are the limitations of BMI?

There are many limitations of BMI that stem from the fact that BMI is not an accurate measurement of health or fitness on an individual level. These include height and muscle mass.

Height: The BMI calculation states that a taller person is just a scaled up normal person, however, taller people tend to have slighter frames on average.

Muscle Mass: The BMI calculation does not differentiate between muscle mass or fat mass. A lean bodybuilder would be considered obese under BMI measurements.

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

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

It's really important that our BMI 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 BMI Calculator over any of those other inferior calculators online.

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

Check 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.

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

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

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