US Envelope Sizes

Standard North American envelope sizes

A1

5^1/8 x 3^5/8 inches

A2

5^3/4 x 4^3/8 inches

A6

6^1/2 x 4^3/4 inches

A7

7^1/4 x 5^1/4 inches

A9

8^3/4 x 5^3/4 inches

6¾

6^1/2 x 3^5/8 inches

#9

8^7/8 x 3^7/8 inches

#10

9^1/2 x 4^1/8 inches