

The maximum size for a flat provides plenty of room to put lots of material in the envelope. * Large Envelopes exceed one or more of the letter size maximum dimensions. Be no more than 12 inches high x 15 inches long x ¾ inch thick.Have one dimension that is greater than 6⅛ inches high OR 11½ inches long OR ¼ inch thick.The words large envelopes and flats are used interchangeably. The Postal Service uses the word “flats” to refer to large envelopes, newsletters, and magazines. A letter that contains items such as pens, pencils, or keys that create an uneven thickness.Priority Mail International CP 000 000 000 US. A letter that has a delivery address parallel to the shorter side of the mail piece. Priority Mail Express International EC 000 000 000 US.A letter that has clasps, strings, buttons, or similar closure devices.A letter that is more than 4¼ inches high or 6 inches long and is less than 0.009 inch thick.A letter that has an aspect ratio (length divided by height) of less than 1 ⅓ or more than 2½ (a square envelope has an aspect ratio of 1, making it non-machinable).
#Usps mailing envelope download
For a list of non-machinable characteristics, download the non-machinable characteristics (PDF) document. The Postal Service charges extra postage because mail pieces that are rigid, square, or unusually shaped, often jam postal equipment and are difficult to process. Customers can be unpleasantly surprised that they must pay extra postage when, for example, they mail a square greeting card.


Orders and usage of the envelope have steadily declined over the past several years while production and fulfillment costs have continued to rise. Augustine, FL 32084) and is available only through The Postal Store ® at /store/home. This is a Priority Mail ® Flat Rate envelope that features the Castillo de San Marcos Priority Mail stamp image (issued on January 24, 2021, St. Since 2003, the United States Postal Service ® has produced the Pre-Paid Flat Rate Stamped Envelope. Mailing and Shipping Services Discontinuance of the Priority Mail Pre-Paid Flat Rate Stamped Envelope
