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New USPS Mailing Regulations in 2023

Posted on March 22, 2023
Written by Ken LaLone and David Nisley
Tags: Mailing

What changes have been made to the USPS’s bulk mail programs? Coughlin explains how to organize and package mail for saturation, marketing, periodical, and First Class campaigns.


In January 2023, the United States Postal Service introduced a set of new postal rates and regulations. The postage rates increased across the board, including single piece postage, parcel postage, flat rate postage, and bulk rate postage.  Another change affects how mailing pieces, called flats, are packaged for the Post Office. Staying up to date on postal regulations ensures that companies using the USPS for a direct mail campaign continue to save time and money!

The Basics: What are the types of bulk rate mailings?

Bulk postage rates are lower than First Class because various steps have been done prior to the USPS receiving the items and require less sorting.

Saturation Mail: Promotional mail send to every residential and business address in a targeted area or zip code. Thanks to a lower postage rate, it can be an affordable strategy to communicating with a large area.

Marketing Mail: This is also known as Bulk Mail or Standard Mail. Like saturation mailings, this is used for advertising and can include flyers, catalogs, and newsletters. However, Marketing Mail doesn’t blanket an entire area. It targets specific addresses using data selected by the mailer.

Periodical Mail: Mail sent at regular intervals, such as magazines, newspapers, and other publications. This type of mail is subject to specific rules regarding minimum frequency of publication and content requirements in order to qualify for lower postage rates.

What changed (besides the prices)?

Long story short: The USPS has changed their requirements on how you need to package “flats” in order to qualify for the lower bulk mailing rates.

Let’s back up a bit: A flat is a large envelope, newsletter, or magazine that has at least one dimension longer than 6 1/8”, or 11 ½” or is more than ¼” thick. There are maximum dimensions for mailing as flats as well. They can be no longer than 12” in height or 15” in length, or more than ¾” thick. The piece must be flexible, have four square or rounded corners with less than a 1/8” radius, and be uniformly thick. They can be unwrapped, sleeved, wrapped, or enveloped.

In order to qualify for bulk mail rates, flats need to have a minimum of 200 pieces in the mailing, an intelligent mail barcode*, an address list that has been CASS Certified**, and complete addresses including zip code or zip+4 codes***.

* This is generated by mail processing software linked to postal databases

* CASS (Coding Accuracy Support System) certification verifies the accuracy and validity of a company’s mailing list. It checks that the addresses on the mailing list are valid, complete, and properly formatted according to USPS standards. The process also corrects any errors or inconsistencies in the mailing list and adds any missing information, such as ZIP codes, carrier route codes, and delivery point barcodes.

***Don’t worry. We’ll take care of this, too.

So now what?

Before January 2023, flats were prepared to be shipped by simply organizing them by route and placing in sacks provided by the USPS. Now, flats prepared at Marketing Mail, Periodical, or First Class postage rates must be:

  1. Bundled into groups secured by rubber bands, organized by address categories determined by mail processing software
  2. Placed into bundles so that the address is on the same side of all mail pieces.
  3. Placed into specific covered Flat Trays, still provided by the USPS. Each tray may not hold more than 70 pounds of mailing pieces or contain different categories of mail.
  4. Enclosed with the included lid. Lids are green on one side and white on the other. Periodical or Marketing mailings should be covered with the white side of the lid showing. First Class mailings should be covered with the green side of the lid showing.
  5. Secured with two flat plastic straps. They MUST be made of plastic. They may NOT be metal buckles or rope. They MUST be sealed by melting the ends together, tying the straps into a knot, or using self-locking straps. The USPS does NOT provide these straps.

For larger mailings, trays can be placed onto pallets, without lids and straps, and shrink-wrapped.

What about Saturation Mailings?

They can still be organized and delivered to the USPS in sacks. Boom. Done.

Is now a good time to mention that Coughlin can handle all of this?

Our team keeps up to date on all of these regulations so you don’t need to. Whether you simply need help sealing the trays or want to have Coughlin manage the entire process of printing, addressing, boxing, strapping, paper working, and dropping off at the post office…we’re here!

Contact us for a free consultation about your next direct mail campaign!