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upcoming USPS dimension requirements questions

  • Sep 15, 2026 5:51 PM UTC
  • 13 replies
  • 68 views

info301

I sent this to support but thought I’d put it here in case anyone had some answers already to these questions they could share.

Regarding the upcoming USPS non-compliance fee for missing or inaccurate dimensions. I have questions that the email recently sent out does not address. 

USPS Priority Flat Rate has both boxes, envelopes, and padded envelopes. For boxes, getting the dimensions is easy as they have standard LxWxH dimensions. For the envelopes, like the Priority Flat Rate Envelope, the packaging is flexible. USPS only gives LxW as dimensions, as height dimensions, as well as the other dimensions, can vary based on what is put into the package. This is also true for Ground Advantage when shipping something in a regular Bubble Mailer envelope, which is also of a flexible material.

1) Are USPS Priority Flat Rate mailers excluded from these requirements to enter dimensions since USPS knows the dimensions of their Flat Rate mailers?

2) Are bubble envelopes included in the requirement for dimensions, whether USPS Flat Rate padded envelopes or regular unbranded bubble envelopes when used for USPS Ground Advantage? 

3) If so, can we put in a standard average dimension for envelope-style mailers based on the known LxW and estimating height even if it varies?

4) If Flat Rate mailers are not excluded from the requirements, since other USPS Priority Flat Rate boxes are always the same dimensions as the boxes are provided by USPS, can it be programmed into ShipStation to autofill that information. For example, when selecting a USPS Priority Small Flat Rate box, can it autofill the outside dimensions of the box to what USPS states as 8-11/16" x 5-7/16" x 1-3/4" ? 

4) IMPORTANT: Looking back at some of my prior shipments, it appears that even though I have not filled in dimensions for a shipment, sometimes dimensions appear in the Shipment Record at the right of the order viewing screen post shipment, and they do not agree to the Flat Rate box or envelope dimensions for the product used. I checked the product's listing in the Products area of ShipStation to see if the dimensions were coming from the Product's shipping presets, and they are not, as no dimensions are listed there. They seem to be coming from the dimensions of the product itself in the WooCommerce store. (?) This should not be prefilling in as the shipment dimensions in Shipstation, as the product dimensions are for packing info and do not agree to the box or envelope dimensions and are an entirely separate thing.

5) If it is pre-filling in the shipment dimensions from a product's dimensions as listed in the store, will this prevent the safeguards you say will be built in when you say “to help you avoid future fees, starting in late September, you will see an error if package dimensions are missing for USPS shipments.” ?

6) If SmartFill is enabled in ShipStation, but I manually put in package dimensions, which does the system use - my manually entered dimensions or whatever the last similar product orders used? If the latter then I need to turn off SmartFill, as sometimes different packaging is used depending on shipping location and other factors. Should I turn SmartFill off in advance of this non-compliance fee issue to prevent it autofilling incorrect dimensions and preventing the “safeguard” warning above?

7) How much are the fees if something goes out with an incorrect dimension because of these issues, and how will it be collected? Is there tolerance for flexible style bubble mailers? Will the package just get returned? 

I hope some of these factors can be addressed before the fees roll out. Thanks for any community help or Shipstation help considering these questions in advance of this new USPS development.

13 replies

  • Community Manager
  • Sep 15, 2026 6:32 PM UTC

Hi there,

Thank you for raising these questions!

1 & 2) Are Flat Rate mailers and bubble envelopes included?

  • Priority Mail Flat Rate (Envelopes, Padded Mailers, & Boxes): EXCLUDED, as far as I can see. 

  • Regular / Unbranded Bubble Mailers (USPS Ground Advantage): INCLUDED. Any non-flat rate commercial parcel requires Length, Width, and Height. 

3) How to handle dimensions for flexible bubble mailers?

Yes, use standard average dimensions and round up.
For flexible bubble mailers, measure the outer length and width of the mailer, estimate the average thickness/height when packed, and round every dimension up to the nearest whole inch (per USPS rules).

4) Autofilling Flat Rate Dimensions

Because Flat Rate packaging is pre-defined by USPS, selecting the specific packaging type (e.g., USPS Priority Small Flat Rate Box or Flat Rate Padded Envelope) tells the system everything it needs. You do not need to manually enter or autofill dimensions for Flat Rate selections. 

5) WooCommerce Product Dimensions & Safeguards

If your WooCommerce store passes product dimensions into the order line items, ShipStation may pull those in to populate the package fields if no package preset is selected.

  • Does this bypass the missing dimension safeguard? Yes. Because the dimension fields contain numbers, the system recognizes them as present.

  • How to fix this: If your product dimensions don't match your actual shipping packaging, the best practice is to set up Shipping Presets or Automation Rules 

6) SmartFill vs. Manual Entry

  • Manual entry always wins: If you type in dimensions manually, your manual input overrides SmartFill.

  • Should you turn it off? If you frequently use different packaging for the same items and find SmartFill predicting the wrong packaging, turning it off under Settings > Shipping > Packages is a good idea to prevent it from pre-filling an incorrect box size.

7) Fees, Collection, and Returns

  • Will packages be returned? No. Packages are not returned for missing or inaccurate dimensions. 

  • How are fees collected? USPS uses Automated Package Verification (APV) scanners on processing belts. If a package is flagged, it is delivered to the customer, and the postage adjustment fee is charged to your postage balance post-shipment.
  • Fee amounts & Timeline:

    • USPS plans to introduce dedicated non-compliance fees tentatively in early 2027. 

    • The late September notice refers to ShipStation rolling out proactive warnings/errors inside the software to help you catch missing dimensions now so you avoid penalties later. 

    • Currently, USPS already assesses adjustments if a package exceeds 1 cubic foot or 22 inches in length without dimensions entered.

       

Hope this clears up the confusion with your packaging setup!


info301
  • Author
  • Employee
  • Sep 16, 2026 5:59 PM UTC

Thank you for these! One more question regarding your statement that “ If a package is flagged, it is delivered to the customer, and the postage adjustment fee is charged to your postage balance post-shipment.” Will we get some sort of email notice when this happens, so that we can see what went wrong and address it going forward?


  • Community Manager
  • Sep 16, 2026 6:08 PM UTC

Thank you for these! One more question regarding your statement that “ If a package is flagged, it is delivered to the customer, and the postage adjustment fee is charged to your postage balance post-shipment.” Will we get some sort of email notice when this happens, so that we can see what went wrong and address it going forward?

I can’t say for certain, but my assumption it will work like any other adjustment and it will be pulled from your ShipStation balance. 

You can read more about adjustments here: https://help.shipstation.com/hc/en-us/articles/29256492262683-ShipStation-Carrier-Adjustments


info301
  • Author
  • Employee
  • Sep 16, 2026 6:58 PM UTC

Thanks so it sounds like we probably will not get notified, and will have to add a task to periodically review that report via View Carrier Transactions. I didn’t even know it existed, so good to know.

If there is a suggestion box, I’d like to request that whenever something affects our ShipStation balance that is NOT user-initiated like printing a label or adding funds, that it triggers an email. That way if USPS charges us for making an error, we will know. Otherwise we have another chore to monitor this. 

 


  • Community Manager
  • Sep 16, 2026 8:26 PM UTC

If there is a suggestion box, I’d like to request that whenever something affects our ShipStation balance that is NOT user-initiated like printing a label or adding funds, that it triggers an email. That way if USPS charges us for making an error, we will know. Otherwise we have another chore to monitor this. 

 

You can treat this thread as a suggestion box. I will let the product team know about this note, and see if we can add this feature. 


sales244
  • Employee
  • Sep 25, 2026 11:59 AM UTC

Does anyone know if they are going to charge the non-compliance fee even if the rate would have been the same anyway?  i.e. it’s a 2 lb ground advantage package going to a non-rural zip and you entere 12x8x3 but it’s really 12.25x8.25x3.25 ?

Also has USPS said exactly when this will take effect?  So far all I’ve heard is “early 2027”.


sales244
  • Employee
  • Sep 25, 2026 1:02 PM UTC

Thanks so it sounds like we probably will not get notified, and will have to add a task to periodically review that report via View Carrier Transactions. I didn’t even know it existed, so good to know.

If there is a suggestion box, I’d like to request that whenever something affects our ShipStation balance that is NOT user-initiated like printing a label or adding funds, that it triggers an email. That way if USPS charges us for making an error, we will know. Otherwise we have another chore to monitor this. 

 

agreed 100%.  This should have been happening years ago


sales436
  • Employee
  • Oct 1, 2026 4:32 PM UTC

The first time I was made aware of this change was today when all my USPS orders had a rate error.
I did not get an email update from shipstation, and I cannot find any article on shipstation about the change. Did I miss it?

I have found the official USPS page https://about.usps.com/postal-bulletin/2026/pb22700/html/updt_001.htm

 

I wish we had been made aware of this sooner I could have enabled smartfill for dimensions sooner (ive never had a use for it before so it was off).

Also 99.9% of our packages are “soft” small packages that rarely even hit the dimensional weight discount. I’m not sure smartfill will even be helpful as the soft packaging can change if I don’t exactly pack things the same way each time. And then they could just change shape during shipping.

I can foresee this is going to be a huge pain once the fee goes into effect and I have to start battling USPS about dimensions.

Edit: I’ve also just realized my first workflow disruption, I can no longer just buy the postage I need for a batch of orders, because I can’t see the postage without dimensions anymore. So I can either manually calculated based on postage paid, or just guess. I don’t like either options. 


ctobin
  • Employee
  • Oct 1, 2026 5:12 PM UTC

I have a different issue regarding dimensional requirements! I ship a lot of gift cards, most of which go 1st class mail as a letter.

Entering dimensions does not work for a letter, envelopes are not 1” thick, and thus, I get “Invalid rate. Provided dimensions are out of allowable range for selected package type.”

Right now I am unable to ship gift cards at the letter rate and I would love a fix. Thank you so much!

 


  • Community Manager
  • Oct 1, 2026 5:29 PM UTC

I have a different issue regarding dimensional requirements! I ship a lot of gift cards, most of which go 1st class mail as a letter.

Entering dimensions does not work for a letter, envelopes are not 1” thick, and thus, I get “Invalid rate. Provided dimensions are out of allowable range for selected package type.”

Right now I am unable to ship gift cards at the letter rate and I would love a fix. Thank you so much!

 

I’ll confirm, but I don’t believe letters will require dimensional requirements. Would the price drastically change if you round up to the nearest inch? 


ctobin
  • Employee
  • Oct 1, 2026 5:38 PM UTC

Letters should not require dimensions to ship, but currently that is how ShipStation is set up. 

The price would drastically change, because everything would have to go at a package rate instead.


  • Community Manager
  • Oct 1, 2026 5:42 PM UTC

Letters should not require dimensions to ship, but currently that is how ShipStation is set up. 

The price would drastically change, because everything would have to go at a package rate instead.

I dropped into an account and saw you can generate a rate by ignoring height, as long as you include length and width of the letter


ctobin
  • Employee
  • Oct 1, 2026 5:52 PM UTC

Looks like that works. Thanks Juan!