Around 29.5 - but it's a pile a crap as my BF is in the "healthy" zone and I carry a lot of muscle mass. If you read the disclaimer it says it's not suitable for atheletes or sports people or bodybuilders.
BMI in my opinion should never be taken as an indication of health as it has been, but generally an indication of how much stress your joints are under, regardless if your a body builder and your BMI says overweight/obese it means in later life you could have joint problems caused by your life style.
I may be wrong but thats always been my way of looking at it

KaHn