How long are the seatbelts on Airplanes?

Question

How many inches are they?

What size waist would you need to have to fit on one without requesting an extension?

Answer 1

They are pretty long. I don't want to offend you but if you are very fat most people would get first class for a bigger seat.

Answer 2

I had heard that they will fit up to a size (Male) 70 waist when using the seatbelt extender. The seatbelt extender is the "demonstration seatbelt" that the flight attendants use.

District of Columbia seatbelt laws say that a seatbelt must fit 47.2" waist. It doesn't specify whether or not its for an aircraft, but I think its for all methods of travel.