Calculated my BMI (body mass index) for my weight at the start of this blog - 340 pounds, 5 ft 9 in tall.
50 - Super Obese!
Oddly enough, it's the same calculation for men or women. Not entirely accurate (doesn't account for muscle, etc.), but still a good general indicator.
I used this CDC government calc.
However, I use this ranking found elsewhere on the interwebs (CDC doesn't differentiate above Obese):