The length measurement is based on the bottom of the bed. If you look closely at the photos on the Frontgate web site, you'll notice that the headboard is set in from the bottom of the bed. So, the length measurement is for the longest part of the bed, that being the bottom - in other words, the headboard doesn't lie behind the "mattress" for this inflatable bed. The headboard lies within the length of the mattress. So, the actual full length of the twin version is indeed 89 inches, and the actual length of the queen version is 93 inches.
3 years, 4 months ago