Direct Mail Specifications - Letter Size Automation Mail

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Direct Mail Specifications For Letter Size Mailers

When creating a printed piece to be used for automation compatible direct mail, there are a few postal requirements to consider so that your piece can be mailed without incurring postal surcharges.


First, lets talk about size.

What Is A Letter Size?

A letter size is a piece whos final mailing size is between a minimum of 3.5 inches in height and 5.5 inches wide up to a maximum of 6.125 inches in height by 11.5 inches wide. So, a postcard or envelope that falls withing these specifications would be considered a letter size. There is a slight difference if the piece is a folded self mailer. A folded self-mailer is formed of at least two panels created when a single or multiple unbound sheets of paper are folded together and sealed to form a letter-size mailpiece. The maximum height and width for a folded self mailer is 6 inches in height and 10.5 inches wide.


Acceptable Paper Thickness

Any paper thickness can be used as long as the minimum thickness of the final piece is at least 0.007 inches in thickness.

For mailers printed on cover stock like a postcard with no folds we suggest using at least 80# dull or gloss coated cover.

If you use coated book stock with at least one fold you will need to use at least a 70# weight. Bond paper will require at least a 20# weight, but we recommend 24# so that it will better withstand the postal processing equipment.


Return Address

A return address is recommended and for some classes of mail like non-profit, it is required. The return address should be placed either in the upper left corner of the piece or the address panel and should be at least 8pt type.


Address Panel Space Requirements

The recommended space for an address panel on a letter size piece is withing the OCR read area. The OCR read area is a space defined by these boundaries.

Left: 1/2 inch from the left edge of the piece

Right: 1/2 inch from the right edge of the piece

Top: 2.75 inches fromthe bottom edge of the piece

Bottom: 5/8 inch from the bottom edge of the piece


In addition to the address panel, there needs to be a postage area space to allow for either a precancelled stamp or a postal indicia. If you don't already have your own postal indicia, contact your printer or mail house. You may be able to mail your piece using theirs.  Include a clear space of 0.375" around the entire indicia. If placing physical stamps, place them at least 0.25" from the top or right edge.