Learn About Bulk Mailing and Tracking → USPS New Bundling Rules for Presorted Flats
Scott
Postage $aver Software
Updated July 25, 2025
If you prepare presorted flat-sized mail, listen up!
Rubber bands, string and twine are no longer acceptable for securing bundles of flat-sized mail. Instead, mailers are required to use plastic strapping or similar material.
Rubber bands have long been a problem for the Postal Service because, well, they break. And they follow Murphy's Law in that they tend to break at the worst times, scattering the pieces they were supposed to hold and gumming up the works.
But the good news is that for many mailers, the new rules also eliminate the requirement to prepare bundles. The downside to that is that some rates are based on the sorting level of the bundle, and without bundles, you'll pay a slightly higher postage rate. So you'll have to decide whether the hassle of bundling using strapping instead of rubber bands is worth any savings in postage.
USPS prohibits rubber bands for securing most bundles of presorted flats, effective 7/1/25.
But many mailers will no longer be required to prepare bundles at all.
ScottPostage $aver Software
Updated July 25, 2025
If you prepare presorted flat-sized mail, listen up!
Rubber bands, string and twine are no longer acceptable for securing bundles of flat-sized mail. Instead, mailers are required to use plastic strapping or similar material.
Rubber bands have long been a problem for the Postal Service because, well, they break. And they follow Murphy's Law in that they tend to break at the worst times, scattering the pieces they were supposed to hold and gumming up the works.
But the good news is that for many mailers, the new rules also eliminate the requirement to prepare bundles. The downside to that is that some rates are based on the sorting level of the bundle, and without bundles, you'll pay a slightly higher postage rate. So you'll have to decide whether the hassle of bundling using strapping instead of rubber bands is worth any savings in postage.
Which mail does the new banding rule apply to?
The new rules apply to bundling flat-size presorted mail only.
For mailers preparing presorted flats, the new rules are different depending on which class of mail you are preparing, as follows:
First Class Presort Flats:
If you are mailing presorted letter-size (including postcard size) pieces, you can continue to use rubber bands to secure your pieces so they don't become un-stacked in the tray. Nothing changes for letter-sized mail.
Also, if you are just a regular mailer sending mail at regular stamp or meter postage rates, none of this applies to you. You can still put rubber bands around you mail if you want.
Also, if you are just a regular mailer sending mail at regular stamp or meter postage rates, none of this applies to you. You can still put rubber bands around you mail if you want.
For mailers preparing presorted flats, the new rules are different depending on which class of mail you are preparing, as follows:
First Class Presort Flats:
Nonbarcoded flats:
Marketing Mail Flats:- Bundling is no longer be required or allowed.
- The way postage is calculated has not changed. Postage is based only on the weight of the piece.
- Bundling is no longer required or allowed.
- All postage is now be based on the sorting level of the tray, where in the past it was based on the sorting level of the bundle. That means your pieces may be in higher rate categories after the change, depending on how your mailing sorts out.
Every Door Direct Mail (EDDM):
- For most mailers, preparation of EDDM remains the same. Bundles are still required.
- Rubber bands, string and twine are still allowed, except if you are preparing EDDM bundles on pallets. If the bundles will be prepared on pallets, you must use strapping or shrink wrap as discussed below.
Nonbarcoded flats:
Periodical Flats:- Bundling is now optional if your mailing has 500 pieces or less, but is still required for larger mailings.
- Bundling is now optional for nonbarcoded nonmachinable flats of any quantity.
- If you are mailing nonbarcoded flats that are machinable, then bundling is optional for some mailings of more than 500 pieces, but still required for others.
If any of the bundles you would be creating are sorted to 5-digit schemes or 3-digit schemes, then you are still required to prepare those bundles, but for 5-digit and 3-digit non-scheme destinations, you are not. In practical terms, that means if there are any 5-digit or 3-digit scheme bundles in your mailing, you must prepare all of the bundles, since you can't mix bundled and unbundled pieces in the same tub,
- If you decide to prepare bundles, rubber bands, string and twine will NOT be allowed. See below for what will be allowed.
- The postage will about be the same whether you prepare bundles or not. The only reason to continue to prepare bundles for a mailing where they are not required will be for possibly faster service.
- Bundling is now optional for barcoded flats of any quantity.
- If you decide to prepare bundles, rubber bands, string and twine will NOT be allowed. See below for what will be allowed.
- If you decide not to prepare bundles, postage will be based on the sorting level of the tray, where with bundles, it is based on the sorting level of the bundle. That means without bundling, your pieces may be in higher rate categories depending on how your mailing sorts out.
- Follows the corresponding rules shown above, except that in trays that have nonbarcoded and barcoded pieces, they must be bundled to separate nonbarcoded pieces from barcoded pieces.
Nonbarcoded and barcoded flats:
Presorted Bound Printed Matter Flats:- Bundling is now optional if your mailing has 500 pieces or less, but is still required for larger mailings.
- If you have 500 pieces or fewer and decide to prepare bundles, rubber bands, string and twine will NOT be allowed. See below for what will be allowed.
- If you have 500 pieces or fewer and decide not to prepare bundles, postage will be based on the sorting level of the tray, whereas with bundling, it is based on the sorting level of the bundle.
That means your pieces may be in higher rate categories depending on how your mailing sorts out, but you will not be charged an outside county per-bundle charge for outside-county bundles you no longer prepare.
- For combined mailings of nonbarcoded and barcoded flats, trays that have nonbarcoded and barcoded pieces must be bundled to separate nonbarcoded pieces from barcoded pieces.
Nonbarcoded and barcoded flats:
- Bundling is still required.
- Rubber bands, string and twine are not be allowed. See below for what will be allowed.
What can we use instead of rubber bands?
Here is the new rule for how to band a bundle of flats:
203.4.5 Securing Bundles of Flats
Bundles must be able to withstand normal transit and handling without breakage or injury to USPS employees, and are subject to the following requirements:
a. Bundles must be secured with two or more cross-strapped bands or shrink-wrapped with one or more cross-strapped bands. Banding includes plastic bands, and similar material. Use of string, rubber bands, wire or metal banding is not permitted except as provided in (c) below.
b. Bundles without polywrap materials must be cross-strapped (encircle the length and girth of the bundle at least once). Additional bands may be used if none lies within 1 inch of any bundle edge.
c. With the exception of First-Class Mail flats placed in flat tubs, rubber bands and twine/string are not permitted to use as banding materials to secure bundles.
d. Banding tension must be sufficient to tighten and depress the edges of the bundle. Loose banding is not allowed.
e. Newspapers that are placed in a flat tray and entered as exceptional dispatch may use only one strap around the middle to prevent potential damage.
Questions? Get in touch.
203.4.5 Securing Bundles of Flats
Bundles must be able to withstand normal transit and handling without breakage or injury to USPS employees, and are subject to the following requirements:
a. Bundles must be secured with two or more cross-strapped bands or shrink-wrapped with one or more cross-strapped bands. Banding includes plastic bands, and similar material. Use of string, rubber bands, wire or metal banding is not permitted except as provided in (c) below.
b. Bundles without polywrap materials must be cross-strapped (encircle the length and girth of the bundle at least once). Additional bands may be used if none lies within 1 inch of any bundle edge.
c. With the exception of First-Class Mail flats placed in flat tubs, rubber bands and twine/string are not permitted to use as banding materials to secure bundles.
d. Banding tension must be sufficient to tighten and depress the edges of the bundle. Loose banding is not allowed.
e. Newspapers that are placed in a flat tray and entered as exceptional dispatch may use only one strap around the middle to prevent potential damage.
Questions? Get in touch.
