ISO C series (envelopes)

C10 envelope size

C10 envelope measures 28 x 40 mm (1.1 x 1.57 in). Part of the ISO C series (envelopes).

28 x 40millimetres

1.1 x 1.57inches

331 x 472pixels @ 300 dpi

Dimensions in every unit

Unit	Width x height
Millimetres	28 x 40 mm
Centimetres	2.8 x 4 cm
Inches (decimal)	1.102 x 1.575 in
Inches (fraction)	1 1/8 x 1 9/16 in
Points (1/72 in)	79.4 x 113.4 pt
Picas	6.61 x 9.45 pc

Pixel dimensions by resolution

Resolution	Pixels	Megapixels
72 dpi	79 x 113 px	0 MP
96 dpi	106 x 151 px	0 MP
150 dpi	165 x 236 px	0 MP
200 dpi	220 x 315 px	0.1 MP
300 dpi	331 x 472 px	0.2 MP
600 dpi	661 x 945 px	0.6 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)	34 x 46 mm	1.339 x 1.811 in
0.125 in bleed (each side)	34.4 x 46.4 mm	1.352 x 1.825 in

How many C10 envelope fit on a press sheet

Sheet	Without bleed	With 3 mm bleed
A4	50-up	36-up
A3	105-up	72-up
SRA3	128-up	81-up
Letter	45-up	36-up
Tabloid 11 x 17 in	90-up	72-up
12 x 18 in	112-up	78-up
13 x 19 in (Super B)	136-up	98-up
B2 (offset)	300-up	210-up

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

The √2 system

C10 envelope has an aspect ratio of 1 : 1.4286 — 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 C10 envelope?

C10 envelope is 28 x 40 mm, which is 1.1 x 1.57 in (1 1/8 x 1 9/16 in).

How many pixels is C10 envelope at 300 DPI?

331 x 472 pixels at 300 dpi, or 165 x 236 at 150 dpi.

Sources & data

Dimensions per the relevant standard; see sources.