Twin vs Twin XL mattress?

I have a twin mattress, I know, but I'm not sure if I had a standard double or twin XL. I did not even knew that there were two different sizes of twins until the other day when I decided it was time for a new and measured the length of my bed. He left between 77-78 inches. Every step that I found online, said a standard of 75 inches and a XL 80. So I'm not sure if the sizes run a little long or a little short. I'm 5'8, so you do not need that extra inch of my body, but if my current mattress is a size XL and the short term, I do not buy a standard and be 73-74 inches and then have a 5-inch space between the end of my mattress and frame. Anyone know?

It is likely that a double standard. There should be a label sewn into the mattress to be established if it were an XL. If you measure the mattress he has and is between 77 and 78 inches, then I bet which is a standard. Over time, mattresses musher gets a little bit and going to get a bit of length and width due to this. So your current mattress would be slightly longer than a new being. Your frame will be longer than necessary for a standard mattress to accommodate the mattress to resolve over time. You could get one XL and just get in the box a bit if you want. I've done before.