Bolt pattern size, big and small?

Hello all, just got a new to my 67 Dart 270 and looking for a set of 15in steelies but i keep seeing several different bolt pattern sizes. I see some that say 5x4 and some 5x4.5 so tad confused. I wont be able to get to the car for a few days to measure it since im out of town. Any and all help is very appreciated. Thank you.