I have shown a table of the different sized envelopes available with the measurements
in Metric (mm) and Imperial (Inches). If you would like to view the different sizes
of paper available, you can click here to view my blog about that.

There are so many different types of envelopes currently on the market, sometimes
it’s hard to find the exact one you need. They are available in lots of different
sizes, styles, thicknesses, materials, colours and finishes.

The most popular envelope sizes are C6, C5, C4 and DL.Hopefully my little diagrams
will shed some light on the sometimes confusing task of finding the correct envelopes
for your needs.

I have also shown a table of the different sized envelopes available with the measurements
in Metric (mm) and Imperial (Inches). If you would like to view the different sizes
of paper available, you can click here to view my blog about that.

There are dozens of sizes of envelopes currently on the market, in different formats of size, style, thickness and colour. The commonly used envelope sizes are C5, C6 and DL. The ISO or international organisation for standardization has set the some standards for paper and envelopes too. The international standard ISO 269 defines several envelope standards envelope sizes. For postal purposes ISO 269 and DIN 678 define the following envelope formats:

C6 - 114mm × 162mm
DL - 110mm x 220mm
C6/C5 - 114mm x 229mm
C5 - 162mm x 229mm
C4 - 229mm x 324mm
C3 - 324mm x 458mm
B6 - 125mm x 176mm
B5 - 176mm x 250mm
B3 - 250mm x 353mm
E4 - 280mm x 400mm

The DL envelope format is the most widely used business envelope size. DL, which was probably at one time the abbreviation for DIN Lang (Deutsche Industries Norm, Long), is now identified as Dimension Lengthwise by ISO 269.