Envelope Sizes

Envelopes made simple.


Many envelopes list their size but some are standard sized and include the following.
Envelope Size Guide by OfficePad

C4 Envelopes

The simplest to explain, this is a fraction larger than A4 paper and allows you to send A4 paper without folding it. Sized at 324x229mm.

DL Envelopes

The DL envelope is probably the most used envelope and it can take an A4 sheet of paper folded into three (two folds).
This means it is 110x220mm or about one third the size of A4 paper.

C5 Envelopes

C5 is about half the size of A4 and will take A4 paper folded in half. Size of 229x162mm.

C6 Envelopes

A very small envelope, the C6 will take A4 paper folded into one quarter it's normal size. Usually 114x162mm.

C3 Envelopes

A large envelope, this takes sheets of A3 paper without folding them. A3 paper is twice the size of A4. A C3 envelope is usually 457x324mm.

Opening types

A number of opening types are also available on envelopes.
Envelope Type Guide by OfficePad


Pocket envelopes have a rectangular shaped flap on the short side of the envelope.


The wallet has a rectangular flap along the long edge of the envelope.


The banker is probably the least common envelope and is the type which opens along the long flap with a triangular shaped flap.

Seal Types

A number of seal types can be chosen for many brands.

Self Seal

Possibly the most common. Press the two parts of the envelope together and the pre-glued flaps will hold shut. These create less waste, less hassle but they have a limited shelf life of a few years.

Peel and Seal

These have a much longer shelf life than self-seal envelopes. There is a strip you have to remove before pressing the envelope shut. The strip obviously creates waste but these envelopes can usually last for many years on the shelf.


Gummed have the longest shelf life but need to be moistened before pressing the envelope shut.

Royal Mail and Envelope Sizes

Due to Royal Mail changing their delivery prices according to size, you may prefer to buy smaller envelopes than you have in the past. Sending your mail in a DL envelope instead of C4 can save you considerable costs, however check the height of the envelope too against their size charts. The disadvantage will be folded documents and the advantage being financial saving.