This article has information related to purchasing shipping labels from the Shipstation. If you purchased your shipping label through the PayPal Shipping Center, visit our PayPal Shipping Center for more information.

The USPS uses Automated Package Verification (APV) to confirm that all shipments match the details on the label. If you entered incorrect package weight, package size, or destination address, it could result in underpaid postage. If you haven't paid enough to cover the postage for your package, USPS will deduct the differential amount of the label automatically from your PayPal account. If you've overpaid, it'll refund the excess amount automatically to your PayPal account.

What if I don't agree to the underpaid label charges?

You can see the adjustment report from your "Settings" page in ShipStation. If you think you were charged for underpaid postage incorrectly, you'll need to contact USPS directly at verifypostagehelp@usps.gov to dispute the charges.

How can I avoid underpaid postage?

Follow these tips to avoid underpaid postage:

1. Weight - Make sure that you report correct weights while purchasing labels. Always round off your weights to the next number. For example, a weight of 7.2 oz is 8 oz and not 7 oz.
2. Dimensions - Report accurate dimensions when purchasing labels. Dimensional weight (volumetric weight) may apply to your packages and providing correct dimensions will help you avoid underpaid postage.
3. Correct address - Make sure that you enter the correct address and correct zip code. Any discrepancies in this would result in extra charges.
4. Match the label to the packaging - USPS provides a wide range of shipping options to help you meet your mailing needs. Make sure that the label you're using matches the packaging. For example, if you're using a flat rate box, you should also use a flat rate label. Similarly, anything in a priority mailbox requires a priority mail label.
5. Double check the zip code - Confirm that the origin address is up to date, and you've marked the correct zip code for the destination.