ISO C series (envelopes)
B6/C4 envelope size
B6/C4 envelope measures 125 x 324 mm (4.92 x 12.76 in). Part of the ISO C series (envelopes).
Dimensions in every unit
| Unit | Width x height |
|---|---|
| Millimetres | 125 x 324 mm |
| Centimetres | 12.5 x 32.4 cm |
| Inches (decimal) | 4.921 x 12.756 in |
| Inches (fraction) | 4 15/16 x 12 3/4 in |
| Points (1/72 in) | 354.3 x 918.4 pt |
| Picas | 29.53 x 76.54 pc |
Pixel dimensions by resolution
| Resolution | Pixels | Megapixels |
|---|---|---|
| 72 dpi | 354 x 918 px | 0.3 MP |
| 96 dpi | 472 x 1,225 px | 0.6 MP |
| 150 dpi | 738 x 1,913 px | 1.4 MP |
| 200 dpi | 984 x 2,551 px | 2.5 MP |
| 300 dpi | 1,476 x 3,827 px | 5.6 MP |
| 600 dpi | 2,953 x 7,654 px | 22.6 MP |
300 dpi is the usual target for printed photos and artwork; 72–96 dpi is screen resolution.
Document size with bleed
| Bleed | Millimetres | Inches |
|---|---|---|
| 3 mm bleed (each side) | 131 x 330 mm | 5.157 x 12.992 in |
| 0.125 in bleed (each side) | 131.4 x 330.4 mm | 5.171 x 13.006 in |
How many B6/C4 envelope fit on a press sheet
| Sheet | Without bleed | With 3 mm bleed |
|---|---|---|
| A3 | 2-up | 2-up |
| SRA3 | 2-up | 2-up |
| Tabloid 11 x 17 in | 2-up | 2-up |
| 12 x 18 in | 2-up | 2-up |
| 13 x 19 in (Super B) | 3-up | 3-up |
| B2 (offset) | 8-up | 6-up |
| B1 (offset) | 16-up | 15-up |
Simple grid imposition with no gutters or gripper margin; real layouts may fit fewer.
The √2 system
B6/C4 envelope has an aspect ratio of 1 : 2.592 — close to √2 (1.4142). Folding or cutting it in half across the long side produces the next smaller size in the series with the same proportions, and two sheets side by side form the next larger size. This is why scaling between sizes in the series (for example on a photocopier) never crops or distorts the page.
This size is listed in the Wikipedia article on paper sizes under “International envelope and insert sizes”. Historic and regional sizes can vary between sources and mills.
Similar sizes
Frequently asked questions
What are the dimensions of B6/C4 envelope?
How many pixels is B6/C4 envelope at 300 DPI?
Sources & data
- Listed in the Wikipedia article “Paper size” (CC BY-SA 4.0).