C Series Paper Sizes (C0-C10)
Complete reference for ISO C series envelope sizes from C0 to C10 with dimensions in mm, inches, and pixels.
| Size | mm | inches | pixels (300 DPI) |
|---|---|---|---|
| C0 | 917 x 1297 | 36.1 x 51.1 | 10831 x 15319 |
| C1 | 648 x 917 | 25.5 x 36.1 | 7654 x 10831 |
| C2 | 458 x 648 | 18.0 x 25.5 | 5409 x 7654 |
| C3 | 324 x 458 | 12.8 x 18.0 | 3827 x 5409 |
| C4 | 229 x 324 | 9.02 x 12.8 | 2705 x 3827 |
| C5 | 162 x 229 | 6.38 x 9.02 | 1913 x 2705 |
| C6 | 114 x 162 | 4.49 x 6.38 | 1346 x 1913 |
| C7 | 81 x 114 | 3.19 x 4.49 | 957 x 1346 |
| C8 | 57 x 81 | 2.24 x 3.19 | 673 x 957 |
| C9 | 40 x 57 | 1.57 x 2.24 | 472 x 673 |
| C10 | 28 x 40 | 1.10 x 1.57 | 331 x 472 |
About the C Series
The ISO C series paper sizes are based on an aspect ratio of 1:sqrt(2) (approximately 1:1.414). This means that when you fold a sheet in half along its longer side, the resulting halves have the same aspect ratio as the original sheet. C sizes are designed as envelope sizes for corresponding A series paper.