Earlier this month, the United States Postal Service’s new regulations for folded self-mailers (FSM) went into effect. The regulations include updated criteria for mailers’ size, shape, tabbing and closure methods.

You probably get one of these handy little pieces in your mailbox just about every day. So what is a folded self-mailer, anyway? The postal service defines an FSM as an un-enveloped mail piece made up of one or more sheets of paper, folded and held together by adhesives. Folds divide paper into “panels,” which can be horizontal or vertical and are roughly equal in size.

FSMs can be customized with internal attachments and enclosures, such as coupons or return envelopes. And they stay sealed with the help of glue or sticky tabs—but they’re never stitched, stapled, or otherwise bound. (If they are, the USPS calls them “booklets.”) Still confused? Newsletters, promotional mailers, event brochures, and Netflix discs are common examples of FSMs.

One subset of changes covers how mailers can be designed. Here are the basics:

  • Size. Mailers were once allowed to be as large as 6 .125” x 11.5”. Now, they’ll have to shrink slightly. The maximum dimensions permitted are 6” x 10.5”; the minimum is 3.5” x 5”.
  • Paper weight. FSMs must be printed on slightly denser paper than before. For mailers weighing an ounce or less, 70# book paper is required; mailers of more than an ounce must use 80# book weight paper. An FSM’s total weight can be no more than 3 ounces.
  • Address placement. Wide variation in where addresses are printed has posed problems for optical character recognition machines. The postal service has requested that addresses appear on the middle to left side of a mailer’s panel. On a tri-fold newsletter, the mailing address must appear on the middle of the three panels.
  • Other stuff. The USPS has also offered guidance for creative touches, such as pop-open panels, die-cutout holes, and internal attachments, and technical elements, such as the recommended coefficient of paper-to-paper friction (in case you’re wondering, it’s 0.26-0.34).

For the full details on all of the new regulations, check out this PDF released by the USPS. Of course, you don’t have to commit the FSM decision tree to memory or lose sleep over whether you placed your wafer-seal tabs far enough away from the mailer’s trailing edge. That’s our job.

If you have any questions about these new guidelines—and what they mean for your direct mail—don’t hesitate to get in touch.