Cannelli Printing Company in West Haven CT

How to make a custom envelope

We often find ourselves making custom envelopes for our customers because they are looking for an unusual size envelope or because they want to use a specialty paper stock. The first step in designing a custom envelope is to select a size. Standard social and correspondence envelopes are available in Announcement (A-size) and Baronial envelopes.

A-size envelopes have a square flap and are constructed with side seams. The most commonly used sizes are:

A2 – 4.375 x 5.75

A6 – 4.75 x 6.5

A7 – 5.25 x 7.25

A8 – 5.5 x 8.125

A10 – 6 x 9.5

Baronial envelopes are constructed with a pointed flap and diagonal seams. The most commonly used sizes are:

No. 4 – 3.625 x 5.125

No. 5 – 4.125 x 5.5

No. 5 1/2 – 4.375 x 5.75

No. 6 – 4.75 x 6.5

Lee – 5.25 x 7.25

The sizes listed above are simply guidelines for standard social and correspondence envelopes. The benefit of designing a custom envelope is that you can select your own paper stock, envelope size and flap style.

The first step in making a custom envelope involves die cutting. A steel rule die will be made that is the exact shape of the flat, unglued envelope.



The die is mounted to the press and paper stock is loaded.


The die cut sheets come out of the press ready to be glued.


The sheets are loaded into the gluer/folder and the side panels are glued and folded.


The last step is to apply a piece of permanent tape to the flap. The end user will remove the tape when they are ready to mail.

Custom Envelopes


Some things to consider when designing a custom envelope:

Paper stock should be a minimum of 100# text and a maximum of 100# cover.

Check with the USPS to make sure your envelope is approved for mailing. There could be a surcharge in postage for an envelope that’s an oddball size.