Our current bath tub w/enclosure is 58.5 inches long (wall-to-wall). The width is 30 inches. Bath tubs at Lowe's and Home Depot list the lengths of their tubs as 5 feet long. My question is: Are bath tubs lengths a full 5 feet long or like lumber are the measurements a little bit less? Thank you all for your help. I truly appreciate it.

It really depends on the manufacturer of the tub and the composition of the tub.

Enameled steel tubs are generally exactly 5" from flange to flange.

Cast iron tubs are generally a little proud of 5" from flange to flange.

Acrylic and fibreglass tubs are usually a little shy of 5" -- The variance can be anywhere from 3/16" to 5/8".

And composite tubs can vary from an 1/8" to 7/8".

Bottom line: Almost any tub can be made to fit an opening (within tolerances, of course) with a bit of ingenuity and the right tools.

If the tub is too big, you break out the surface planer -- If it's too small, you break out the box of butt strips.

I was going though home Depo the actual spec not the description, and they seemed to range from 59 inches to 63 inches when they are called 5 ft, have you went there and actually measured them,

Great advice above. When you get your new tub, you will want to know the rough opening to bare studs(sheetrock, tile etc removed) and get the right tub to make install as smooth as possible. Im guessing you will need a true five foot tub (60" end to end) Good luck and please keep us posted on your project.

Enclosure is usually less than 60" because it attaches over finished wall. If you have 1/2" backing board over studs and 1/4" tile attached to the backing board than the dimension of the enclosure is just about as you listed it.

The average tub size is 60 X 30"
Good luck, Tom