Standard international paper and envelope sizes
Paper sizes
The ISO 216 standard, which includes the commonly used A4 paper size, is the international standard for paper size.
The most common of the A sizes is A4 (210 x 297 mm) which is the size most letters are sent in, and the size you’d find in a standard office printer.
Each A size is half of the size of the next number down, so two pieces of A4 could be made by slicing an A3 piece of paper in half. This is helpful as it means A sizes all have the same aspect ratio. If you had artwork set at one A size, you could feasibly print it at another as long as the resolution is high enough.

Standard international paper sizes table
Size | mm | cm | in |
---|---|---|---|
A0 | 841 × 1189 | 84.1 x 118.9 | 33.1 × 46.8 |
A1 | 594 × 841 | 59.4 x 84.1 | 23.4 × 33.1 |
A2 | 420 × 594 | 42 x 59.4 | 16.5 × 23.4 |
A3 | 297 × 420 | 29.7 x 42 | 11.7 × 16.5 |
A4 | 210 × 297 | 21 x 29.7 | 8.3 × 11.7 |
A5 | 148 × 210 | 14.8 x 21 | 5.8 × 8.3 |
A6 | 105 × 148 | 10.5 x 14.8 | 4.1 × 5.8 |
A7 | 74 × 105 | 7.4 x 10.5 | 2.9 × 4.1 |
A8 | 52 × 74 | 5.2 x 7.4 | 2.0 × 2.9 |
A9 | 37 × 52 | 3.7 x 5.2 | 1.5 × 2.0 |
A10 | 26 × 37 | 2.6 x 3.7 | 1.0 × 1.5 |
Standard envelope sizes
The international standard for envelopes is the C series of ISO 269. The standard paper sizes can fit inside the envelopes either flat or folded. See the table below for sizes and examples.
Size | mm | cm | in | |
---|---|---|---|---|
C4 | 229 x 324 | 22.9 x 32.4 | 9.01 x 12.75 | A4 unfolded or A3 folded once |
C5 | 162 x 229 | 16.2 x 22.9 | 6.37 x 9.01 | A5 unfolded, A4 folded once, or A3 folded twice |
C6 | 114 x 162 | 11.4 x 16.2 | 4.48 x 6.37 | A6 unfolded, A5 folded once, or A4 folded twice |
C7 | 83 x 112 | 8.3 x 11.2 | 3.26 x 4.40 | A7 unfolded, A6 folded once or A5 folded twice |
DL | 110 x 220 | 11 x 22 | 4.33 x 8.66 | A4 folded into thirds |
Fold examples for envelopes


For more advice on paper and envelope sizes, contact Inspired Print Solutions.