ISO C series (envelopes)

C4 envelope size

C4 envelope measures 229 x 324 mm (9.02 x 12.76 in). Envelope for unfolded A4 sheets and catalogues.

229 x 324millimetres

9.02 x 12.76inches

2,705 x 3,827pixels @ 300 dpi

Dimensions in every unit

Unit	Width x height
Millimetres	229 x 324 mm
Centimetres	22.9 x 32.4 cm
Inches (decimal)	9.016 x 12.756 in
Inches (fraction)	9 x 12 3/4 in
Points (1/72 in)	649.1 x 918.4 pt
Picas	54.09 x 76.54 pc

Pixel dimensions by resolution

Resolution	Pixels	Megapixels
72 dpi	649 x 918 px	0.6 MP
96 dpi	866 x 1,225 px	1.1 MP
150 dpi	1,352 x 1,913 px	2.6 MP
200 dpi	1,803 x 2,551 px	4.6 MP
300 dpi	2,705 x 3,827 px	10.4 MP
600 dpi	5,409 x 7,654 px	41.4 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)	235 x 330 mm	9.252 x 12.992 in
0.125 in bleed (each side)	235.4 x 330.4 mm	9.266 x 13.006 in

How many C4 envelope fit on a press sheet

Sheet	Without bleed	With 3 mm bleed
A3	1-up	1-up
SRA3	1-up	1-up
Tabloid 11 x 17 in	1-up	1-up
12 x 18 in	1-up	1-up
13 x 19 in (Super B)	2-up	2-up
B2 (offset)	4-up	4-up
B1 (offset)	9-up	9-up

Simple grid imposition with no gutters or gripper margin; real layouts may fit fewer.

The √2 system

C4 envelope has an aspect ratio of 1 : 1.4148 — 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.

Frequently asked questions

What are the dimensions of C4 envelope?

C4 envelope is 229 x 324 mm, which is 9.02 x 12.76 in (9 x 12 3/4 in).

How many pixels is C4 envelope at 300 DPI?

2,705 x 3,827 pixels at 300 dpi, or 1,352 x 1,913 at 150 dpi.

Sources & data

Dimensions per the relevant standard; see sources.