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Envelope FAQ's

Your Questions About Envelopes Answered Here

Ok, so envelopes might not be something you think about every day, but when you do need them you'd be surprised how many different types, sizes, styles and technical terms are involved. We've put together a list of the questions we get asked most about envelopes to help you out. Our friendly expert staff are also available to chat to if you have any questions too - give us a call on 01273 486026 during office hours, or drop an email to


Questions about envelope paper

What does GSM mean in paper and envelope terms?

In paper terms, GSM stands for Grams per Square Metre. The higher number of gsm, the thicker the paper. To put this in ‘real life’ terms:

  • 80gsm – 90gsm = About the thickness of standard printer paper. This tends to be the thickness of budget white envelopes
  • 120gsm = The thickness of a quality envelope, such as a ‘Conqueror’ envelope. We have a large range of coloured envelopes in 120gsm thickness
  • 160gsm – 180gsm = This is around the thickness of a flyer. In terms of envelopes, 160-180gsm is a luxury envelope. Being thicker and more sturdy, it is also used for gusset envelopes
  • 225gsm = Pretty much as thick as paper can get before it becomes card! Our 225gsm Coloured Envelopes tend to be used for exclusive invitations and high-end mailings
  • 350gsm and up = This is considered card, so very sturdy. Great for sending items you don’t want to bend.

What is a laid envelope?

Laid refers to the paper finish of the envelope. Laid is a textured finish with a ribbed effect which is sometimes found on greeting envelopes. Here's an example of what laid paper looks like:

laid paper envelopes

What is a hammer envelope?

A hammer envelope means the envelope is made of hammer finish paper, which has a bumpy texture, often used for prestigious greeting envelopes.

hammer paper envelopes

What is wove paper envelope?

Wove paper is kind of your ‘standard’ smooth paper type. Like writing paper it isn’t ribbed or watermarked.

Questions about envelope openings & closures

What is envelope peel & seal?

Peel and seal refers to the closure of the envelope. A peel and seal envelope is pre-glued, with a strip of paper you peel off to expose the glue, allowing you to seal the envelope with no licking (like the old school envelopes!).

What is a self-seal envelope?

A self seal envelope closes and sticks without the need for glue or water. You press the pre-glued flap down for a secure seal. These are often used for large mailings

What is the difference between a gummed envelope and a gummed mailing envelope?

A gummed envelope is the traditional style envelope with a water soluble gum strip that you lick to seal the envelope.

Gummed mailing envelopes also have the same water soluble gum strip, but the flap is specially designed to go through a mailing machine, so the machine can seal them. Mailing houses use such machines, so these envelopes are used for large scale direct mail. We stock a range of coloured mailing envelopes.

Questions about different types of envelopes

What is a gusset envelope?

A gusset envelope is an envelope that has expanding sides to allow more capacity. Gusset envelopes are often used for mailing brochures and thick documents.

gusset envelopes

What is a pocket envelope?

A pocket envelope has an opening on the short edge of the envelope, like the pic below:

pocket envelope

What is a wallet envelope?

A wallet envelope has an opening on the longer edge of the envelope, like the photo below:

wallet envelope

What is a banker envelope?

A banker envelope has a triangular flap to close. This is often found on Greeting Envelopes.

banker envelope


Questions about envelope printing

Can you print on coloured envelopes?

Yes, you can print on coloured envelopes. It is recommended to print only black however, as coloured printing is unpredictable when it mixes with the colour of the envelope. Printing black on top of coloured envelopes is very effective – see below as an example, or go to our Printed Envelopes page for more examples.

Printed envelopes

What is foil block printing?

Foil block printing, also called hot foil printing or foil stamping, is when metallic or pigmented foil is hot pressed onto paper to leave the design of the dye on the paper. This gives a very stylish and luxurious result. If you’re interested in foil printing on envelopes call us on 01273 486026 for more info.

Printed envelopes

Is foil block printing the same as hot foil printing?

Yes, both terms refer to the same method of printing. This is also sometimes called foil stamping. See above question for more info.

Can you print on bubble bags?

Yes, we can print on bubble bags. This generally needs to be done at manufacturing stage so the print is applied to the flat sheet material, prior to making into a bubble bag envelope. It can look pretty awesome, but is for large quantities only.


Questions about envelopes, just because…

Is it true that a woman got cockroach eggs in her tongue from licking an envelope?

Although it’s a pretty great story to freak people out with while they’re licking envelopes, it’s not true. 

You can freely lick as many envelopes as you like and even if you get a paper cut you can be happy in the knowledge that a family of cockroaches will NOT grow in your tongue.

If you’re still a little uneasy, then be sure to buy peel & seal envelopes. No licking involved!

What does ‘envelope face’ mean?

When somebody with bushy eyebrows makes an angry face, it looks like an envelope. Definition c/o Urban Dictionary 

envelope face

Questions about addressing envelopes

What is the proper way to address an envelope?

The correct way to address an envelope in the UK is as below:

Addressees’ name
House number and street name
Locality name (if needed)
Full postcode

Here’s an example:

How to address an envelope

For further info about the proper way to address an envelope, including international address standards, see our blog post.


Questions about envelope sizes

What do terms like C6, C5 and DL mean?

These are terms that refer to envelope sizing. Our Envelope Size Guide page will help you with all you need to know about sizing terms. Or you can download our printable Envelope Size Guide

How can I work out which size envelope I need?

Your first bet is to measure the item you wish to put in the envelope. If this is a standard size piece of paper, such as A4 or A5 paper, then it is easy to get the right size envelope for you. Simply swap the "A" for a "C" in envelope sizes. For example, A4 paper will fit into a C4 envelope. For thicker documents or products / objects with some depth, it can be slightly trickier to work out the size you need. Your best bet is to get a couple of samples to try. Call us on 01273 486026 for advise and to order free envelope samples.