Mailing, USPS, Postal Regulations

Simple Guidelines for USPS Mailings (That Aren’t Postcards)

The envelope is classic direct mail, but how sure are you that you’re planning to mail the right one for your campaign?

Not all envelopes are created equal. In fact, in the eyes of the U.S. Postal Service, it’s not that important if your mailpiece is technically considered an envelope or a folded self-mailer. After all, both formats seal a folded piece of paper, just in different ways. What matters more than anything else is its size.

If you choose to stand out in the customer’s mailbox by not mailing a #10 envelope or a postcard, here’s what you need to know to avoid any “sorry, you can’t do that” surprises.

Know Your Letters

You may think of a letter as something mailed in an envelope, but for the purposes of getting through its processing equipment, the USPS has a more expansive view.

To qualify as a letter, a mailpiece must be rectangular and meet these dimensions:

  • At least 3-1/2” high x 5” long x 0.007” thick
  • No more than 6-1/8” high x 11-1/2” long x ¼” thick

By the way, the length is the measurement of the side that’s parallel to the address.

Sounds simple enough, right? But to mail at the lowest rates possible, you’ll also have to make sure that your envelope or FSM is also machinable. It has to get through the USPS system, and that’s a really big deal if you also want to mail in larger amounts for the presort rates.

So what’s nonmachinable? A mailpiece that has clasps or buttons, is overly rigid or unevenly thick, or weighs more than 3.5 ounces, among other characteristics.

Tip: Another way to save money is to mail your campaign as Marketing Mail, unless it carries content that must be mailed as First Class. Consult helpful mailing class guide for further information.

Know Your Flats

Whatever you call them – flats or large envelopes – these are bigger mail pieces than letters. They’re rectangular, with four square corners, or finished corners with a radius greater than 1/8” inch.

To qualify as a flat, a mailpiece must be rectangular and meet these dimensions:

  • At least 6-1/8” high x 11-1/2” long x 1/4” thick
  • No more than 12” high x 15” long x 3/4” thick

Remember, with great size comes great postage. You’ll be paying more for additional weight, which can make a substantial difference at First Class rates. In addition, any pieces that fail to meet standards for uniform thickness or flexibility can be charged at parcel rates.

Tip: Fold and tab your flat-size mailer to mail at the lower, letter-size rate.

Want a full run down of USPS direct mail guidelines? Check out this link!

Know Your Parcels

Parcels are boxes that offer marketers a chance to stand out regardless of whether they’re mailed in First Class or as Marketing Mail.

To qualify as a parcel, a mailpiece should meet these dimensions:

  • At least 3” high x 6” long x ¼” thick
  • No more than 108” long and girth (distance around the thickest part of the box) combined, and 70 pounds in weight. An exception is for mailings using USPS Retail Ground or Parcel Select.

Tip: A machinable box must measure no more than 27” long x 17” width x 17” high and weight more than 25 pounds (with exceptions) to be eligible for lower rates.

Wrapping it up

  • To close up your folded self-mailer with seals or wafer tabs, follow these tabbing requirements.
  • Reconsider other ways to make a #10 eye-catching, like real personalization, high-quality bleed-to-the edge images, or an involvement device.
  • Reshape or downsize your mailing piece to meet your campaign’s marketing objectives while saving money.

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