This might be a stupid question, but if you are measuring a tub to buy the same size for a remodel, should you measure the top part that you can see or do you need to add inches to account for the sides that are right now butted up to tile, so I don't know how much fartehr it goes out. There is a built in cabinet right next to it, so it is very hard to know.
Also- it is a kohler tub (I can see the label on it) so I was not expecting it to be a weird size. The top of it is 58.12 inches long and 30 inches wide. Most standard tubs seem to be 60 x 30... so I am don't know if I have a weird size (and likely will have to knock out the built in next to it and have it rebuilt) or if it is actaully a 60 inch wide tub and I just am measuring wrong because I can only measure the top.
Re: how to measure a tub for remodel? (what you can see or is it bigger)?
You lose roughly an inch of exposed tub to cement board and tile (per side) depending on the thickness of your tile. If that is sitting on the edge of your tub surround then that would account for the loss in your measurements. I would assume it is built that way because of the built in cabinet next to it - there is nowhere to recess the cement board with a flush built-in.
Why are you ordering the new bathtub before pulling the old?