ISO C series (envelopes)

C6/C5 envelope size

C6/C5 envelope measures 114 x 229 mm (4.49 x 9.02 in). Long envelope for A4 folded in thirds.

114 x 229millimetres

4.49 x 9.02inches

1,346 x 2,705pixels @ 300 dpi

Dimensions in every unit

Unit	Width x height
Millimetres	114 x 229 mm
Centimetres	11.4 x 22.9 cm
Inches (decimal)	4.488 x 9.016 in
Inches (fraction)	4 1/2 x 9 in
Points (1/72 in)	323.1 x 649.1 pt
Picas	26.93 x 54.09 pc

Pixel dimensions by resolution

Resolution	Pixels	Megapixels
72 dpi	323 x 649 px	0.2 MP
96 dpi	431 x 866 px	0.4 MP
150 dpi	673 x 1,352 px	0.9 MP
200 dpi	898 x 1,803 px	1.6 MP
300 dpi	1,346 x 2,705 px	3.6 MP
600 dpi	2,693 x 5,409 px	14.6 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)	120 x 235 mm	4.724 x 9.252 in
0.125 in bleed (each side)	120.4 x 235.4 mm	4.738 x 9.266 in

How many C6/C5 envelope fit on a press sheet

Sheet	Without bleed	With 3 mm bleed
A4	1-up	1-up
A3	3-up	3-up
SRA3	3-up	3-up
Letter	1-up	1-up
Tabloid 11 x 17 in	3-up	3-up
12 x 18 in	4-up	3-up
13 x 19 in (Super B)	4-up	4-up
B2 (offset)	12-up	12-up
B1 (offset)	24-up	24-up

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

The √2 system

C6/C5 envelope has an aspect ratio of 1 : 2.0088 — 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 C6/C5 envelope?

C6/C5 envelope is 114 x 229 mm, which is 4.49 x 9.02 in (4 1/2 x 9 in).

How many pixels is C6/C5 envelope at 300 DPI?

1,346 x 2,705 pixels at 300 dpi, or 673 x 1,352 at 150 dpi.

Sources & data

Dimensions per the relevant standard; see sources.