Paper Sizes refers to the dimensions of the sheet and are determined by the ISO. In millimeters they are as follows:
A0 841 X 1189 B0 1000 X 1414 C0 917 X 1297
A1 594 X 841 B1 707 X 1000 C1 648 X 917
A2 420 X 594 B2 500 X 707 C2 458 X 648
A3 297 X 420 B3 353 X 500 C3 324 X 548
A4 210 X 297 B4 250 X 353 C4 229 X 324
A5 148 X 210 B5 176 X 250 C5 162 X 229
A6 105 148 B6 125 X 176 C6 114 X 162
A7 74 X 105 B7 88 X 125 C7 81 X 114
A8 52 X 74 B8 62 X 88 C8 57 X 81
A9 37 X 52 B9 44 X 62 C9 40 X 57
A10 26 X 37 B10 31 X 44 C10 28 X 40