Priority Mail Flat Rate Best Practices

Compliance with USPS rules and regulations is an important aspect of being a successful seller and shipper. One rule to definitely keep in mind is that Priority Mail Flat Rate® Boxes must be used with Priority Mail Flat Rate postage. For example, if you have a Medium Flat Rate Box handy, remember that only a shipping label for a Medium Flat Rate Box can be affixed to it! You cannot apply Small Flat Rate Box pricing onto a Medium Flat Rate Box. You cannot apply Flat Rate Envelope pricing to a Legal Flat Rate Envelope, which has a separate pricing structure and is a separate and distinct mailpiece.

The box or envelope you use indicates to the USPS what service you are using. As always, if you are using a barcoded shipping label with Stamps.com, you will receive the discounted Commercial Base rate.

To summarize:

• Priority Mail Flat Rate prices can only be used with USPS-produced Priority Mail Flat Rate Boxes and Envelopes. The pricing category (Envelope, Legal, Padded, Small, Medium, Large) must match the Priority Mail Flat Rate mailpiece.
• Priority Mail Express Flat Rate prices can only be used with USPS-produced Priority Mail Express Flat Rate Envelopes. The pricing category (Envelope, Legal, Padded) must match the Priority Mail Express Flat Rate mailpiece.
• As stated by USPS, “Priority Mail Express packaging provided by the USPS must be used only for Priority Mail Express. Regardless of how the packaging is reconfigured or how markings may be obliterated, any material mailed in USPS-provided Priority Mail Express packaging is charged the appropriate Priority Mail Express price.”

A second caveat: Do not use non-Flat Rate postage on Flat Rate pieces

The opposite is also true. For example, if you use a Priority Mail Flat Rate Box or Envelope, you would not be able to apply a non-Priority Mail Flat Rate label to it. A good rule of thumb: not all Priority Mail is the same, and keep in mind that in addition to Priority Mail Flat Rate pricing there  are also Priority Mail zone/weight-based rates. Tyvek envelopes like the Priority Mail Tyvek Envelope are not Priority Mail Flat Rate Envelopes and do not have their own flat rate mailpiece category in the Stamps.com software—you would select “Large Envelope/Flat” as your mailpiece.

Why is this important?

You definitely want to avoid a scenario in which your recipient or customer has to pay to make up the difference between a Flat Rate service and the postage that was affixed on the mailpiece, or a surcharge that represents the difference between a zone/weight-based rate and the price of a Flat Rate mailpiece.

Avoid postage-due markups! When the USPS receives a shortpaid mailpiece with Commercial Base pricing, it is obligated to charge the difference between the Commercial Base price and the full retail price of that item.

Affixing the wrong postage to a mailpiece may also generate negative seller reviews or cause delays in shipment, as the local Post Office may hold the piece until the surcharge is paid. The good news is that Stamps.com is here to help prevent those pitfalls by making it easy to restock your USPS shipping supplies. To order free USPS packaging, log into your software and click on “Online Store,” which appears beneath “Buy Supplies.”  Click on the “Free USPS Supplies” tab and order the right box or envelope for your mailing needs today!