Have you ever encountered difficulty ordering envelopes because you weren’t sure which type to choose or whether your mail would fit inside? In this envelope size guide, we’ve broken down everything there is to know about envelope sizes to make sure you make the right choice!
Finding The Right Size
There are a range of different envelope sizes, from small to large. Below you can read about each size and see which is ideal for your needs.
DL Envelopes
DL Envelopes are one of the most widely used options available. This envelope accommodates A4 paper folded into thirds lengthways and is usually recognised as the standard type businesses use when mailing out one to three-page letters.
C6 Envelopes
C6 envelopes are ideal for smaller items. Such as A6-sized greeting cards, invitations or small documents like folded A4 sheets of paper. A4 paper will need to be folded in half twice to fit inside of a C6 envelope.
C5 Envelopes
C5 Envelopes are another popular choice as it’s made to fit an A4 piece of paper folded in half lengthways. This type of envelope is more suitable than the DL if you’re posting slightly longer letters.
C4 Envelopes
C4 Envelopes are primarily used for sending A4-sized documents without folding them. This makes them ideal for a variety of purposes, such as business correspondence and sending marketing materials.
C3 Envelopes
C3 Envelopes are primarily used for sending A3-sized documents without folding them. This makes them ideal for sending large documents and are often used in industries like design, engineering and education.
Size Guide
Below you will find a handy size guide for all of the envelopes above that mention their measurements in millimeters, centimeters and inches.
| Envelope Size | Size in Millimeters | Size in Centimeters | Size in Inches |
| DL Envelopes | 110 x 220mm | 11 x 22cm | 4.33″ x 8.66″ |
| C6 Envelopes | 114 x 162mm | 11.4 x 16.2cm | 4.5″ x 6.4″ |
| C5 Envelopes | 162 x 229mm | 16.2 x 22.9cm | 6.4″ x 9″ |
| C4 Envelopes | 229 x 324mm | 22.9 x 32.4cm | 9″ x 12.8″ |
| C3 Envelopes | 324 x 458 mm | 32.4 x 45.8 cm | 12.7″ x 18″ |
At Staples we offer a wide range of different Envelopes all in one place so that you can stock up on all your mailing needs in one convenient place!
