C9 size
40 × 57 mm · 1.57 × 2.24 in · 113.4 × 161.6 pt
Where it comes from
Half of C8: the C8 sheet's long side (81 mm) halves and rounds down to 40 mm — ISO 216's halve-and-floor rule.
Source: Markus Kuhn — International standard paper sizes (CC BY 4.0)
Pixels at print resolutions
| DPI | Pixels (portrait) | Typical use |
|---|---|---|
| 72 | 113 × 162 | legacy screens |
| 96 | 151 × 215 | CSS reference |
| 150 | 236 × 337 | everyday print |
| 300 | 472 × 673 | quality print |
| 600 | 945 × 1346 | fine art / line work |