The location of the delivery address on a letter-size mailpiece determines which dimensions are the length and height of the piece. The length is the dimension parallel to the address as read; the height is the dimension perpendicular to the length. Consequently, the placement of the address may render a piece nonmailable or nonmachinable. On a letter-size piece, the recommended address placement is within the optical character reader (OCR) read area, which is a space on the address side of the mailpiece defined by these boundaries:
a. Left: 1/2 inch from the left edge of the piece.
b. Right: 1/2 inch from the right edge of the piece.
c. Top: 2-3/4 inches from the bottom edge of the piece.
d. Bottom: 5/8 inch from the bottom edge of the piece. [example]