*Edited: These sites calculate BMI for people over 18 years of age! If you are under 18 and with calculate your BMI CLICK HERE!*
For
https://nhlbisupport.com/bmi/:
Underweight = <18.5
Normal weight = 18.5-24.9
Overweight = 25-29.9
Obesity = BMI of 30 or greater
For
https://www.mydr.com.au/tools/bodymass.asp
Less than 19 UNDERWEIGHT
You are under optimum weight for your height. You could afford to gain a little weight.
20 - 25 ACCEPTABLE
You have a healthy weight for your height.
26 - 30 OVERWEIGHT
You are over optimum weight for your height. You may be facing health problems, so losing some weight would be a good idea.
31 + OBESE
You are over optimum weight for your height. You may be facing health risks, so see your doctor to help you achieve a healthier weight.
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Not quite sure why some of the values are different... but it gives you a rough idea of where you are at all the same.