What Bulk and Periodical Mailers Need to Know about the USPS "Flat Tray" Rule

 Postage $aver Software

Effective January 22, 2023, USPS has changed the way "flats" are prepared for Marketing Mail (bulk mail) and Periodical Class mail rates. Mailers are required to use "flat trays" (also called "tubs") instead of sacks to submit flats.

USPS tub (flat tray)This is a "flat tray". (Yes, I know it's not flat. But it's used for flats. The flatter trays that you use for letter-sized mail are called "letter trays.")

Previously, Marketing Mail mailers have been required to use sacks (or, in some case, letter trays) for flats. Periodical Class mailers have had the option of preparing sacks using either flat trays or sacks, but are no longer allowed to use sacks. (There are some exceptions ... see below.)

Two important warnings:

What are flats?

Postage Saver software makes postal bulk mailing easy If you have been using sacks to send your Marketing Mail or Periodical Class mail, and the mail is not a parcel, then it is a flat.

A flat is any mail that is rectangular, flexible, and fits at least one of the following requirements, regardless of whether it is a card, envelope, or package: A flat also cannot be "lumpy". In other words, its thickness may not vary more than 1/4" except within 1" of the edges.

* Every Door Direct Mail flats have a different minimum length, but EDDM is not part of this rule change.

How to arrange your mail in a flat tray:

Postage Saver software makes Periodical mailing easy

Do I still need to bundle my mail when using flats trays?

In general, yes, bundling is still required.

But there is a big exception. No bundling is required for a particular tray if all of the bundles in that tray have the same destination and sort level as the tray itself.

For example, if the tray tag says it's a 3D tray going to 770, and the endorsement lines on all of the pieces say 3D 770, then no bundles are used because they are all being sorted just down to the 3-digit level. Bundling serves no purpose if it doesn't separate the mail more finely than the tray does.

But if the endorsement lines in at least one of the bundles in that tray say 5D 77005, then all pieces in the tray must be bundled, because there are enough pieces going to 77005 to be worth keeping them separate from the rest of the tray (but not enough pieces to be worth their own 77005 tray).

For each tray, Postage $aver figures out whether bundles are used, and shows that on the Mail Preparation Instructions report.

How do I create "columns" if bundling causes my pieces to roll up?

You're not really supposed to have rolled bundles, and that's especially important when using flat trays. Bundles are supposed to lie flat. If the rubber band tension causes the pieces to roll up, use rubber bands that won't do that. Here's what USPS says about bundling flats:

Exceptions to the flat trays rule:

USPS has provided the following exceptions to the flat tray rule where sacks are still permitted.

For Periodical Class and Marketing Mail, sacks can still be used for nonpalletized flats as follows: Note that the Periodical Class per-container charge for sacks is more than the charge for the same mail if prepared in flat trays.

For "Every Door Direct Mail" sacks can still be used.

Postage $aver Pro and Postage $aver Lite do not support the exceptions to the flat trays requirement.

Questions? Ask us and we'll do our best to answer.

Scott started Postage Saver Software in 1994. He's been helping small businesses and nonprofits save postage with postal bulk mail for more than 25 years. Scott's based in Austin, Texas. He's happy to answer your bulk mailing questions!