Post Office

Standard Preparation

Designing Letters and Cards for Automated Processing

Characteristics and Content

  • Maximum for cards at card rate is 4 1/4 inches high, 6 inches long, and 0.016 inches thick
  • Maximum for letters and other cards is 6 1/8 inches high, 11.5 inches long, and .25 inches thick
  • Minimum of 3.5 inches high, 5 inches long, and 0.007 inches thick
Maximum Weight
  • Standard mail machinable is 3.5 ounces
Other Machinablity Standards
  • Regular shape, with adequate flexibility and rigidity
  • Tabbing for self-mailers or pieces with open edges
  • Clasps, strings, stables, buttons, or protrusions that might impede or damage the mail or mail processing equipment

To be sure a mailing qualifies, please don't hesitate to bring us a sample copy. If necessary, we will verify acceptability with our contact at the Rock Hill Post Office.

Machinable Standard

This is the preferred and easiest way to prepare your mailing for standard mail. To meet the requirement for machinable mail, your mailing must be either a post card, a sealed envelope, or, if folded paper, tabs at each end of the mail piece sealing all loose sheets together.

Non-Machinable Mail

Flats include mail that is oversized for letter mail. Flats receiving discount rates must now be addressed in portrait mode as opposed to the traditional landscape mode. Flats must be placed in white mail tubs obtained from our office. A report must accompany the mailing with the department name. budget number to be charged to and the total pieces in the mailing. All the requirements listed for machinable mail can be applied to flat mail pieces.

Requirements to Qualify a Mailing for Discount Service

  • A report must accompany the mailing showing the number of pieces in each zip code and conclude with the total number of pieces in the mailing.
  • An Ancillary Endorsement must appear on each piece. The most commonly used at Winthrop is returned service requested 
  • Mailing cannot be offering anything for sale (e.g., tickets or fees).
  • Mailing must be a minimum of 200 pieces.
  • Mailing must have 128 permit indicia in upper right hand corner of the address side of the mail piece.
  • Not to be used for time sensitive mailing, a maximum of 3 days is requested for processing at the Winthrop Post Office. The U.S. Postal service allows itself from 2-9 days for delivery. In most cases, the mailing is delivered in 2-4 days but standard mail receives the lowest handling priority.

Download instructions (pdf - 27.5 KB) on how to prepare discount letters and cards.

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