more than 6⅛ inches on its shorter side or,.For First Class mail only (including regular mail and Presorted First Class), a card that is postcard-sized is a postcard, not a letter.Ī flat is a rectangular card or envelope that is larger or heavier than a letter, meeting AT LEAST ONE of the following: If your letter is an unusual size, shape or material, or have unusual content, find out if you have to pay a surcharge. weighs no more than 3½ ounces (applies to First Class letters only).

(except at least 0.009' thick if the piece is larger than 4¼' x 6').

Postcard-size pieces are classified as letters.įor Presorted First Class mailings only, the maximum postcard size is 6' x 9'.Ī letter is a rectangular card or envelope that fits ALL THREE of the following: Is your mail a postcard, letter, flat or parcel? Here's the quick answer:Ī postcard is a card (not an envelope) that fits ALL THREE of the following:įor Marketing Mail (bulk mail), the postcard category does not apply.

These are the four main size categories that USPS uses to classify mail and determine postage.

Learn About Bulk Mailing and Tracking → Postcard, Letter, Flat or Parcel Is it a Postcard, a Letter, a Flat or a Parcel? Scott

Usps large flat rate envelope size