When filling out vital statistics about my characters, like height and weight, I always look to their initial play-by. Most celebrities have their height listed somewhere on the Internet. Some even have full measurements. However, more often than not, their weight is not listed. This is when I look to the art of guestimation. To be honest, I've never been good at guessing anyone's height or weight or even the square footage of a house. I'm a writer; numbers aren't my forte.
So, what is a writer to do when the overwhelming need to guestimate something like weight is encompassing? Or rather, what do you roleplayers do? Most Web sites that calculate BMI take into account age and the body's "average"* growth rate, so I imagine in teens, BMI tends to differ drastically when considering bodily development, self-image issues, and fad diets. Should I just list a body type, e.g. athletic, muscular, slim, etc., and just be done with it?*I say that carefully because we all know everyone's body is different.