In response to some questions we have received about envelopes we have provided some answers here:

Q: What size are A4 envelopes?

A: When people refer to an A4 envelope, they usually mean a C4 envelope, which is designed to hold A4 paper unfolded. The C4 envelope is 229 x 324 mm (9.0" x 12.8"). If an envelope was made that was A4 size it would be 210 x 297 mm (8.3" x 11.7") however you wouldn't be able to get an A4 sheet of paper in it without folding it.

Q: What is half A4 envelope size?

A: To hold an A4 sheet folded in half you need a C5 envelope 162 x 229 mm (6.4 x 9.0 in).

Q: What is the difference between C4 and A4?

A: C4 is an envelope size and A4 is a paper size. The C4 envelope is designed to hold a flat, unfolded sheet of A4 paper. The C4 envelope is 229 x 324 mm (9.0" x 12.8") and is 19 mm (0.74") wider and 27 mm (1.06") longer than a sheet of A4 paper at 210 x 297 mm (8.3" x 11.7").

Q: Is C5 bigger than A4?

A: No C5 is smaller than A4, it will hold an A4 sheet folded in half. C5 is 162 x 229 mm (6.4 x 9.0 in) and A4 is 210 x 297 mm (8.3" x 11.7").

Q: What does DL stand for in envelopes?

A: The DL envelope originated in Germany in the 1920's and was known as DIN Lang, but DL is now more commonly expanded to 'Dimension Lengthwise'. (See DL Envelope Size for more information.)

Q: What is a DL envelope?

A: A DL envelope is a long thin business envelope that will hold a sheet of A4 or US Letter paper folded into three equal sections. (See DL Envelope Size for more information.)

Q: What size letters need extra postage?

A: The answer to this depends on where you live. In the US letters over 6.125" x 11.5" (155.6 x 292.1 mm) will require extra postage and in the UK letters over 165 x 240 mm (6.5" x 9.4") will require extra postage.

Q: What is the average size of a postcard?

A: Most postcards these days are A6 size, 148 x 105 mm or 5.8 x 4.1 inches. so this could be considered to be the avarage size of a postcard. (Click here for the maximum and minimum sizes for postcards.)

Q: What are the USPS postcard size requirements?

A: USPS postcards must be between 5" and 6" in length and between 3½" and 4¼" in height. In addition the thickness of the postcard must be between 0.007" and 0.016" (7 - 16 thou or 0.178 - 0.406 mm). (See USPS standard postcard size for more information)

Q: What is a wallet envelope?

A: A wallet envelope is an envelope that has a trapezium shaped flap along the long edge that can come in straight or slightly curved variations. They are the most common envelopes for automated mailings.

Q: What is a gummed closure envelope?

A: A gummed closure envelope is an envelope with gum that needs to be moistened, commonly by licking, before it will stick.

Q: Are C5 envelopes large letter?

A: In both the UK and the US C5 envelopes can be sent using the standard letter postage rate.

Q: How much does a card and envelope weigh?

A: This will depend on the size of the card and envelope, but in general they will weigh less than 100g (3.5oz) and will fall under standard postage rates. If you need to know how much a particular letter will weigh just use a set of kitchen scales to weigh it.

Q: What size is C6 card in inches?

A: C6 card is 4.5 x 6.4 in.

Q: What are the different types of envelopes?

A: The main types of envelopes are Banker, Pocket and Wallet. Banker envelopes are those that you see most often for greetings cards, they have a triangular flap on the long edge. Pocket envelopes have their flap on the short edge, it is usually a trapezium shape. Wallet envelopes also have a trapezium shaped flap, but it is along the long edge.

Q: Does an A4 envelope need a large letter stamp

A: In the UK a C4 envelope that holds A4 paper needs a large letter stamp, as it is bigger than the maximum size for a standard letter. The same is true in the US where the C4 envelope will need to be sent as a flat rather than a standard letter.