Envelope sizes, formats, materials, weights etc.
Description of Envelopes.
There are many things you need to specify about an envelope to identify a particular product.
Size. Most envelopes are more-or-less flat, and these need only two dimensions to specify the
size, but some have a gusset and a third dimension is required to say what is its capacity. Size
may be specified as
Many greetings cards have envelopes of sizes which are not standard in the commercial world. We can
supply in many colours but they are not normally ex-stock. See below for more information about
standard commercial sizes.
- A code such as C4 (which is the correct size to take an unfolded sheet of A4 paper) or DL
(which is the correct size to take an A4 sheet folded with
two parallel folds, to one-third
of its original size). For more information on A, B and C sizes see our
tutorial on paper sizes.
- A pair of dimensions (or occasionally three, see above) which may be in inches or in millimetres.
Material. Envelopes may be made of paper (vegetable fibres) or man-made materials such as polythene
and more exotic materials like Tyvek which is practically untearable.
Some are 'board-backed', which stiffens them, for mailing fragile things such as photographs. You
can buy an envelope stiffener for plain envelopes which does much the same thing.
Colour. They are mostly white (although there are many different whites), or brown (ditto), but there
are numerous coloured stationery sets where headed notepaper, plain notepaper and envelopes are matched.
You can even buy matching correction fluids. Some wage envelopes are translucent.
Weight. Materials for envelope manufacture are made in a variety of thicknesses, which are expressed
as weight per square metre. 70gsm (grammes per square metre) is a lightweight envelope, 90gsm is a
moderate weight, 115gsm is a heavyweight envelope.
The opening can be on the longer edge (wallet or banker envelopes) or the shorter edge
The flap can be rectangular (wallet and pocket) or triangular (banker), but depending on the size,
the material and the manufacturer you don't always get the choice.
Type of seal. The most common are:
Some envelopes can optionally have notched flaps to show evidence of tampering. There are re-useable
envelopes with a string or fastener for internal mail and similar functions.
- Gummed. These need moisture to seal, you can use a damper or lick them.
- Twin-gummed. These are a more secure seal than ordinary gummed, but they still need moisture.
- Self-sealing. A contact adhesive on the meeting surfaces seals the flap.
The two coated surfaces must meet to make a seal.
- Peel and seal. An adhesive on the flap face is exposed by a peel-off strip.
The adhesive will stick to any part of the envelope, so you can fold the
flap down further than intended to adjust the size of the package, and the
envelope will not accidentally seal itself until the strip is removed.
After the strip is removed, it CAN accidentally seal itself!
Window, if any. Many envelopes have a window, through which the destination address on a letter can
be seen. The position of the window may vary from one brand to another. Some manufacturers offer a
choice of position, usually 'high' or 'low'.
Printing, if any. This may include.
- Printed on the inside, for example for security
- Printed outside, such as "Documents Enclosed" wallets, some wage envelopes and internal mail envelopes.
- Printed with sender's name and address etc.
Does the envelope have a gusset? Gusset envelopes (e.g. 'Zambezi' envelopes) have expanding folds
along the edges so they can accept much greater contents.
Punching such as 'Safecheck' wage envelopes.
Padding such as 'Jiffy' and 'Mail-Miser' envelopes.
Self-adhesive backs such as "Documents Enclosed" envelopes.
The last two items in this list are getting into the realms of
It is also important to note the packaging of envelopes. Many are packed in
boxes of 1,000 (e.g. most DL) but larger sizes and heavier weights are commonly
packed 500 or 250 per box.
Standard Commercial Envelope Sizes.
The most common sizes today are the 'C' sizes, plus the ubiquitous DL. All these are sized to take
a few sheets of 'A' sized papers, folded or not. For example C5 envelopes take A5 paper unfolded
but will take A4 folded once or A3 folded twice (to one-quarter of its original size).
Many envelopes sizes are given just in inches or millimetres, and do not conform to any particular
convention. You can usually find one which will do what you need. Bear in mind that when you put
more than a couple of sheets of thin paper in an envelope you need to allow for the thickness of
the contents in sizing the envelope - it will seem to get smaller as you stuff more in it!
If you are doing a mailshot, consider POCKET envelopes (which open along the shorter edge) with a
window. Many people say that they are much easier to fill with papers than banker envelopes.
Bear in mind that paper is not a dimensionally stable material, it moves with changes in its water
content. In addition, interpretations of the size standards may differ slightly from one manufacturer
to another, so envelope sizes will always be approximate.
|C0 ||917 ||x||1297||..*..||36.10 ||x||51.00 |
|C1 ||648 ||x|| 917||..*..||25.50 ||x||36.10 |
|C2 ||458 ||x|| 648||..*..||18.00 ||x||25.50 |
|C3 ||324 ||x|| 458||.....||12.75 ||x||18.00 |
|C4 ||229 ||x|| 324||.....|| 9.00 ||x||12.75 |
|C5 ||162 ||x|| 229||.....|| 6.375||x|| 9.00 |
|C6 ||114 ||x|| 162||.....|| 4.50 ||x|| 6.375|
|C7 ||81 ||x|| 114||.....|| 3.25 ||x|| 4.50 |
|C7/6||81 ||x|| 162||.....|| 3.25 ||x|| 6.375|
|DL ||110 ||x|| 220||.....|| 4.33 ||x|| 8.66 |
* Note that these envelope sizes exceed the maximum size of envelopes
posted via Royal Mail in the UK. The maximum size is 610mm x 460mm x 6mm
thick. The thickness can be up to 460mm for parcels. The maximum length
of rolled packages sent through the UK mail is 900mm. Source: "Handy Guide to
Inland Services", The Post Office, 1998. For up-to-date information contact
the Post Office.
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