

The location and orientation of the delivery address now establishes which dimensions are the length and the height. After the mailpiece is determined to be a letter, then determine if it is mailable. If the mailpiece falls within these dimensions, it is classified as a letter.ġ. For a mailpiece to be eligible for First-Class Mail letter rates, it must be at least 3-1/2 inches by 5 inches by 0.007-inch thick, and no more than 6-1/8 inches by 11–1/2 inches by 1/4-inch thick.

This has been the standard for a number of years. For letters over 1 ounce and large envelopes over 6 ounces, the prices today are lower than before May 14, 2007.ĭetermining the processing category of a mailpiece (letter, large envelope, or package) is dependent solely on the physical dimensions of the piece without regard to address placement. Emphasizing shape has also allowed us to reduce the additional-ounce rate. The First-Class Mail price structure provides opportunities for customers to obtain lower rates if they can reconfigure mailpiece contents into mail shapes that reduce postal processing costs. The following information is provided to clarify how the prices apply to the most common mail shape - “letters.” We now have separate First-Class Mail rate categories for the different mail shapes: postcards, letters, large envelopes (flats), and packages.
