How to design a flat—here are the dimensions to follow:

The delivery address must be in the TOP HALF of the mailpiece.

  • For enveloped or polywrapped pieces and all saturation Carrier Route pieces, the “top” of the mailpiece is either of the shorter edges.
  • For pieces that are not enclosed in envelopes or polywrap, the “top” is the upper edge when the bound edge (or final fold) is vertical and on the right side of the piece.
  • Once you choose a top edge, measure halfway down the piece, and that’s the top half. If you have shorter mailpieces, the address can run into the bottom half if it is placed within an inch of the top edge.
  • The address can be on the front or the back of the mailpiece, but it must be on the same side as the postage. The address may be parallel or perpendicular to the top edge, but not upside-down as read in relation to the top edge.
  • The post office prefers an address as close as possible to the top edge (but not closer than 1/8″). However, they accept the address anywhere in the top half as described above and shown in the examples.
  • Click here to download a helpful: Flats Fact Sheet

Where does the Permit and Return Address go?

  • The postage should appear to the right or upper right of the delivery address, and the return address should appear to the upper left of the delivery address. The very best place for the return address is at least one inch above and one inch to the left of the delivery address.
  • Additional requirements concern the point size and spacing of the address lines.  When Five Maples addresses your piece we will ensure the address meets these additional requirements.

Check out these examples:

Catalog addressed on back cover: “Top” is the upper edge when the spine is on the right.


Large envelope: “Top” is the left or right edge as viewed in this horizontal orientation. The “top half” could be either the left or right half.

For further details and examples, download the following USPS resources:

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