We (Aus) converted in the 70s but still many things are imperial. For example a 1200x2400 sheet of ply is really 1220x2440 (the old 8x4').
That said you have to check because some materials really are metric and you order an "8x4" sheet and get something 1200x2400, bummer if you have designed something with a 1220 pitch.
Rob