Call Us0800 321 3651

Lines open 9am - 5.30pm

0 £0.00
products in your basketto quote Checkout
Ooops no items were found.
Try something else.

Useful envelope and mailing information

Office Monster stocks a wide variety of envelopes for every occasion, in both window envelopes and non-window envelopes and across all sizes from C5 envelopes, C4 envelopes and DL envelopes. All of our envelopes are available in stock for next day delivery and if you spend over £30.00, you will also receive next day delivery free of charge.

Our handy envelope buying guide, will help you decide which envelope you need, covering all areas from the envelope colour which is available in Manilla and White to the envelope window positioning and everything in between. We stock envelopes from all major brands including Q-Connect Envelopes, Basildon Bond Envelopes, Conqueror Envelopes, New Guardian Envelopes, Plus Fabric Envelopes and many more.

Envelope sizes

Choose from a variety of sizes and formats, popular sizes include:

dl envelopes

DL Size

110 x 220mm

Holds an A4 sheet folded twice or an A5 sheet folded once


C5 Size

229 x 162mm

Holds an A4 sheet folded once or an A5 sheet unfolded


c4 envelopes

C4 Size

324 x 229mm

Holds an A4 sheet unfolded & stops creases


Other formats:

board back envelopes link


For items you don’t wish to bend, crease or fold

gusset envelopes link


Expandable envelopes, ideal for sending bulky items

padded and bubble lined envelopes link

Padded & Bubble Lined

Ideal for posting fragile items

Envelopes come in two standard orientations:

Pocket flap on the short edge Wallet Flap on the long edge

Tear-proof and water-resistant envelope, check out the Tyvek® range of envelopes

Tyvek logo


Don’t forget!



Large Letter

Large Letter

Small Parcel

Small Parcel

The size of the envelope affects the postal costs with Royal Mail, further information can be found at Royal Mail

What quality do you require?

Choose from 70gsm (lightweight) to 130gsm (heavyweight) papers.

Heavyweight papers are stronger and, when coupled with a smooth finish, help deliver the right first impression to the recipient.

If you’re looking for a recycled envelope that doesn’t compromise on quality then the Basildon Bond range is for you. The 100% recycled paper is high-white, without the use of bleaching. The window film is biodegradable meaning even the window versions can go in your paper recycling.


Do you need a window?

Windowenvelope1 Windowenvelope2

Window envelopes are useful for bulk mailings, invoices and statements where the recipients address is automatically printed on the document. The size and position of the window is always described with the flap upwards. SIZE is mesaured HEIGHT first and width second ( A x B). POSITION is measured by the distance in from the left-hand side ( C) and up from the base ( D).

What colour do you require?

Most envelopes come in two colours

white manilla envelope

What type of seal?


Peel seal regular

self seal

peal seal