Oversize/Underweight Mail
First-Class mail weighing one ounce or less is nonstandard if it exceeds any of the following size limits:
- 11½ inches in length, or
- 6½ inches in height, or
- ¼ inches in thickness, or
its aspect ratio (length divided by height) does not fall between 1 to 1.3 and 1 to 2.5 inclusive.
There is an additional charge on each piece of mail that is found to be nonstandard. In addition, pieces that are less than:
- 3½ inches in height, or
- 5 inches in length, or
- .007 of an inch in thickness (thickness of a postcard)
are otherwise non-mailable by U.S. Postal Service standards and are subject to return.
First Class
Any mailable matter may be mailed as First-Class Mail. The following materials are considered First-Class matter and must carry postage at First-Class or Priority Mail Rates:
- Matter wholly or partially handwritten or typewritten (including identical copies prepared by automatic typewriter), originals or carbons, invoices (except when they accompany the matter to which they relate), post cards.
- Matter sealed and closed against postal inspection.
- Bills and statements of account.
- Price lists.
- Any business reply mail
- Checks, cancelled or not cancelled.
Priority Mail
Priority Mail is First-Class Mail, but stipulates two- or three-day service. The maximum weight is 70 pounds and the maximum size is 108 inches in length and girth combined.
Standard Mail (A)
The following is considered Third-Class Matter:
- Circulars Catalogs
- Booklets Newspapers
- Merchandise Product Samples
- Photographs Printed Matter
Standard Mail (B)
The following is considered Fourth-Class Matter:
- Packages or Parcels Sound Recordings
- Library Materials Merchandise
- Books Films
- Bound Printed Matter
Each piece of Standard (B) Mail must not exceed 70 pounds in weight and maximum size of 108 inches in length and girth combined.