37"wide, 31" from seat at floor to the back of the hatch, 18"deep (but this is with the stock sub of an 03.5 removed) there's a false floor from the factory on the 03.5 models with a cargo tray that raises everything about 2" leaving you much less room. YOU can remove it, but it's kinda a pain. Really easy to findout, go to the hatch and look at the spare tire, if there's a litte sub in there it's an 03.5. Also outwardly, alot of 03.5's didn't come with roofrack rails.