BMI calculator??

[Aceso]

So, the other day I was looking at my BMI on the calculator online, and it said below 18.5 was underweight, but I was reading a book the other day, and I think it said that below 19.5 was underweight. I was also on the wii fit, and it also said that 19.5 was underweight. I also came up as 18.0 on the online one and 19.5 on the wii fit. Im very confused, which one is right? I have no clue what BMI I am....:confused:

[Fiction]

The online calculator will probably be more accurate as a Wii fit is not that accurate at measuring your weight. As for a healthy weight, it is different for children and should be measured by centile not BMI.
http://www.nhs.uk/Tools/Pages/healthyweightcalculator.aspx
that is the best BMI calculator because it takes into account everything.

Eating Disorders :arrow: VT General Hospital

[ShatteredWings]

<18.5 is considered underweight, however varying slightly around that can be just as unhealthy.

[xgeekyrocksx]

im 18.0 and i dont really count myself as underweight caus... i dont know i just dont think that 0.5 below the mark counts... but maybe it does... gosh i hope not!!!

[Fiction]

it's slightly different for teenagers. Should work it out on percentile from the calculator i linked above :)

[Rex99]

huh well i'm 18.5 and that's real skinny for a guy. Most of my guy friends are like above 20 or 22.