Post Card Specifications
Postcard Spec's.
Postcard Sizes
First Class
Minimum Size: 3.5" x 5"
Maximum Size: 4.25" x 6"
Standard Mail (Letter rate)
Minimum Size: 3.5" x 5"
Maximum Size: 6.125" x 11.5"
Thickness
Must range between .007" and .016" thickness
Nonmailable and Nonmachinable Placement of Address
The placement of the address on a letter-size mailpiece may render a piece nonmailable or nonmachinable. If the length (the dimension parallel to the address) of a letter-size mailpiece is not at least 5 inches, it is nonmailable. If the height (the dimension perpendicular to the length) of a letter-size mailpiece is not at least 3-1/2 inches, it is nonmailable.
Aspect Ratio.
What is it and why it is important.
If the aspect ratio (length divided by height) is not within 1.3 to 2.5 (inclusive), the piece is a nonmachinable letter, which essentially means it will require more postage than a machinable letter.
For example:
a. For a letter-size piece that is 4 inches by 6 inches, if the address is parallel to the 4-inch dimension, it is 4 inches long, which is less than the minimum length of 5 inches required, this piece is nonmailable.
b. A piece that is 5 inches by 8 inches (and within letter-size thickness dimensions) is a letter. If the address is parallel to the 8-inch dimension, the piece is 8 inches long and 5 inches high. The aspect ratio of this piece is 1.6, so it is a mailable letter within machinable dimensions for length and height.
c. For a letter-size piece that is 5 inches by 8 inches, if the address is parallel to the 5-inch (shorter) dimension, the piece is 5 inches long and 8 inches high. The aspect ratio of this piece is 0.625, which is not within 1.3 to 2.5, so it is mailable as a nonmachinable letter.
