Shipments with underpaid postage may result in transit delays, postage dues for your recipient and/or postage adjustments from the carrier. There are three main considerations for avoiding underpaid postage:

Selecting the correct return address

• Ensure you are creating shipments with the correct return address information.

Accurately entering the weight and dimensions of the shipment

• Always weigh and measure your shipments after packaging them. While your packaging may not weigh very much, a discrepancy of 100 g can make a large difference. Depending on the overall weight and service, your packaging may put your shipment into a different weight class for postage.
• Accurately measure the length, width and height of your shipments as dimensional weight may apply. For irregularly shaped parcels, dimensions should be measured as if the piece was rectangular.
  • Ex. When measuring a tube, its diameter should be used for both the shipment height and width.
• Measure the weights of your shipments on an accurate and calibrated package scale. Always round up:
  • To the nearest pound for U.S. postage. Ex. 7.2 lbs should be rounded to 8 lbs.
  • To the nearest ounce for international postage and shipments less than 1 lb. Ex. 4.8 oz should be rounded to 5 oz.
  • To the nearest 500 g for Canadian postage. Ex. 700 g should be rounded to 1000 g (1 kg).

If you import shipments from your store:

• Make sure that the product entries for all of your SKUs contain the correct weights and dimensions including your packaging.
• Verify the accuracy of all information. It is the shipper’s responsibility to provide accurate information as any inaccurate information can result in:
  • Postage adjustments due to insufficient postage
  • Possible shipping delays
  • Undeliverable shipments (returns)
  • Additional administrative fees

Choosing the correct service for your shipment / packaging

• USPS Media Mail postage can only be purchased for shipments solely containing qualifying media content.*
• USPS First Class Mail can only be used for packages less than 1 lb.
• USPS Priority Mail packaging can only be used with Priority Mail postage. This extends to Priority Regional Rate and Priority Flat Rate packaging as well.*

We encourage you to learn more on calculating correct postage from USPS or you can check out our tips on how to properly package your shipments.

*Service availability may vary.