Working between US and UK sites/companies, I often need to flip back and forth between mm/cm and inches/feet. I have them all laid out so I can quickly convert or visualise a measurement relative to and “A” size I know well. Bookmark it if it helps you to have to hand as well.

A0 841 x 1189 mm 33.1 x 46.8 in

A1 594 x 841 mm 23.4 x 33.1 in

A2 420 x 594 mm 16.5 x 23.4 in

A3 297 x 420 mm 11.7 x 16.5 in

A4 210 x 297 mm 8.3 x 11.7 in

A5 148 x 210 mm 5.8 x 8.3 in

A6 105 x 148 mm 4.1 x 5.8 in