Save Time By Doing It Right

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Automated Package Verification

To continue offering affordable shipping options, USPS® has streamlined how postage is checked on packages with Click-N-Ship® and PC Postage® labels. We are bringing new technology to help you accurately pay for shipping—with the intent that it will improve the shipping experience for both shippers and recipients.

USPS is committed to giving you the tools you need for an easy and seamless shipping experience. We've provided some tips below to help you understand the best practices for improving your shipping procedures and how to calculate postage correctly, so you're not overpaying or underpaying.

How to Calculate Postage Correctly

  • Weigh your item and round up

    USPS® rounds up to either the next pound (lb) or ounce (oz). For example, if your package weighs 3 lbs 5 oz, it would be charged at the 4 lb-rate. If you have an item for shipping by First-Class Package® service that weighs 7.3 oz, it must be charged at the 8 oz-rate. This applies to all mail classes—domestic and international.

  • Select the right mail class

    For example, First-Class Package® service can only be used for packages under 15.999 oz; anything over the weight limit must be shipped with Priority Mail® service. And domestic Regional Rate Boxes A and B have 15 and 20 lbs limits respectively.

  • Measure your package

    Measure the length, width, and height of the package. Dimensional (DIM) weight may also apply to your packaging. DIM weight is determined by multiplying a package's length, width, and height and applying a volumetric divisor.1 DIM weight = (L X W X H)/194.


  • Label your package correctly

    USPS provides a wide range of shipping options to help you meet your mailing needs. Make sure that the label you are using matches the packaging. For example, if you are using a Flat Rate box, you should also use a Flat Rate label. Or anything shipped in Priority Mail® packaging requires a Priority Mail label. Also, ensure you place the label on the long side of the box. Labels should not wrap over the ends or edges and all barcodes should face up in the same direction.

  • Double check the zone

    If you are using PC Postage® software, verify that the origin address (or "sent from") is up to date before printing the label. Please note, USPS charges by zones. To get a zone chart for your ZIP Code™ use the Postal Calculator.

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How is USPS® streamlining the automated package verification process? Expand Collapse FAQ question

We've invested in new technologies that automatically detect and correct package postage overpayments or underpayments, bringing USPS in line with industry standards.