C9 paper size and dimensions
C9 measures 40 × 57 mm, which is 4 × 5.7 cm or 1.57 × 2.24 inches. An A9 card fits inside.
Contents of this page
C9, portrait
40 × 57mm
- Centimetres
- 4 × 5.7 cm
- Inches
- 1.57 × 2.24 in
- Pixels at 300 dpi
- 472 × 673 px
- Points (pt)
- 113 × 162 pt
- Area
- 0.0023 m²
- Weight at 80 gsm
- 0.18 g
In a C9 envelope an A9 card (37 × 52 mm) has just 1.5 mm to spare at the sides and 2.5 mm at the top and bottom. A small 38 × 51 mm sticky note fits too. It holds no more than a few words, a number or a tiny picture, and that is exactly its charm.
C9 in every unit
| Unit | Width × height |
|---|---|
| Millimetres | 40 × 57 mm |
| Centimetres | 4 × 5.7 cm |
| Metres | 0.04 × 0.057 m |
| Inches | 1.57 × 2.24 in |
| DTP points (1/72 in) | 113 × 162 pt |
| Area | 22.8 cm², or 0.0023 m² |
| Diagonal | 69.6 mm |
| Aspect ratio | 1 : 1.425 |
C9 in pixels
| Resolution | Pixels | Megapixels | Good for |
|---|---|---|---|
| 72 dpi | 113 × 162 px | 0.02 MP | Screen, preview |
| 96 dpi | 151 × 215 px | 0.03 MP | Screen (Windows default) |
| 150 dpi | 236 × 337 px | 0.08 MP | Large format, posters seen from a distance |
| 300 dpi | 472 × 673 px | 0.32 MP | Offset and digital print |
| 600 dpi | 945 × 1346 px | 1.3 MP | Line art, fine detail |
With 3 mm bleed the document is 46 × 63 mm, which is 543 × 744 px at 300 dpi.
What C9 is used for
- Messages in Advent calendars, fortune slips and tiny love notes
- Packets for spare buttons, beads or seeds
- Wedding and table decorations
C9 between A9 and B9
Like every C size, C9 sits exactly between the A and B sizes with the same number. A9 is 37 × 52 mm, B9 44 × 62 mm, and C9 40 × 57 mm in between. A C9 envelope therefore holds A9, and a B9 envelope would hold C9. C9 cannot be posted, it is far too small.
How many C9 pieces fit on a sheet?
| Sheet | Without bleed | With 3 mm bleed and 5 mm margin |
|---|---|---|
| A4 (210 × 297 mm) | 25 | 18 |
| A3 (297 × 420 mm) | 50 | 36 |
| SRA3 (320 × 450 mm) | 61 | 42 |
C9 compared
| Size | mm | Area | Compared with C9 |
|---|---|---|---|
| C8 | 57 × 81 mm | 46.2 cm² | twice the area |
| B9 | 44 × 62 mm | 27.3 cm² | 120 % of the area |
| C9 | 40 × 57 mm | 22.8 cm² | |
| A9 | 37 × 52 mm | 19.2 cm² | 84 % of the area |
| D9 | 34 × 48 mm | 16.3 cm² | 72 % of the area |
| C10 | 28 × 40 mm | 11.2 cm² | half the area |
Frequently asked questions
How big is C9 in cm?
C9 is 4 cm wide and 5.7 cm tall.
Does A9 fit in C9?
Yes, with 1.5 mm to spare at the sides and 2.5 mm at the top and bottom.
How many C9 pieces fit on A4?
25 without bleed.
How many pixels is C9 at 300 dpi?
472 × 673 pixels, or 543 × 744 pixels with 3 mm bleed.
Is C9 bigger than B9?
No. C9 (40 × 57 mm) sits between A9 (37 × 52 mm) and B9 (44 × 62 mm).