Square Envelopes

Square envelopes are used primarily with announcements, advertising, and specialty greeting cards or other mailings where the sender wants to draw attention to the contents.

The following list shows the name/number designation, envelope dimensions, and approximate maximum enclosure dimensions for some of the more common sizes of this envelope style. Actual dimensions for enclosures will depend on the thickness of the enclosure (paper thickness, number of pages).

5
5 x 5
4.75 x 4.75

6
6 x 6
5.75 x 5.75

6 ½
6.5 x 6.5
6.25 x 6.25

7
7 x 7
6.75 x 6.75

7 ½
7.5 x 7.5
7.25 x 7.25

8
8 x 8
7.75 x 7.75

8 ½
8.5 x 8.5
8.25 x 8.25

9
9 x 9
8.75 x 8.75

9 ½
9.5 x 9.5
9.25 x 9.25

10
10 x 10
9.75 x 9.75

13 ½
13.5 x 13.5
13.25 x 13.25

All measurements in inches: .125 = 1/8 | .25 = 1/4 | .375 = 3/8 | .5 = 1/2 | .625 = 5/8 | .875 = 7/8
These envelope sizes apply specifically to the United States. Standard International envelope sizes differ.