What do I need to know about shipment weight?

All USPS services have maximum weight restrictions. In addition, many service types use the package weight to calculate the postage weight. As such, it’s important to enter accurate weights for each shipment. Weights are measured in pounds (lbs) and ounces (oz).

It is best to measure your package weight using a postage scale. Postage scales differ from a standard home scale, configured for greater precision. There are a few features that you will want to be sure to have:

  • Digital reading: while manual scales work just fine, they provide much greater room for human error. A digital reading ensures a correct reading, which translates to correct postage.

  • Tare weight: allows you to tell the scale what to read as “0” weight, such as an empty scale or empty box.

  • Capacity: consider the size and weight of your packages and be sure that any model you purchase will accommodate these dimensions. For example, scales may have 5lb, 20lb, or 70lb weight limits. In addition, some scales have small trays making reading the display hard for larger packages.

We have some recommendations of models that will serve you well as your business grows. These models all work well with the full version of ShippingEasy.

Once you have your scale, follow these steps to take accurate weight measurements of your packages:

  1. Place the items that will be shipped in the package, along with any additional packing materials. It’s not necessary to seal the box at this point, but you may.

  2. Turn on your postage scale.

  3. Calibrate the scale. If you are using your scale for the first time, calibrate your scale according to the directions in the manufacturer’s user manual.


    This step is not required every time you use your scale.

  4. Verify proper units. Since postage is calculated using pounds and ounces, check that your scale is configured to display weights in these units.

  5. Tare the scale. Follow the directions in the manufacturer’s user manual.


    When you tare the scale, you are telling the scale to ignore the weight of any object on top of the tray at the time of tare. Anything that will be submitted as mail should not be placed on the tray during the tare.

    • If the package fits on the tray well, then tare the scale with nothing on the tray.

    • If you measure your packages or envelopes placed in a container on top of the tray, then tare the scale with the container on the tray.

  6. Weigh the package. Place the prepared package on the scale (or in the container that you tared) and record the resulting weight.

  7. Locate the Weight field within your shipping application. Enter the pounds in the lbs field and the ounces in the oz field.

  8. Select the Update button to refresh the Postage Cost.

Whether you are shipping with ShippingEasy or EasyShip, we will automatically verify that your package weight meets the requirements for the selected Carrier Service.

If you do not have access to a postage scale, you may want to consider using a Flat Rate shipping option. While not always the least expensive option, the postage cost will not vary with your package weight. However, these packages still have maximum weight limits, so you will want to confirm that your contents do not exceed this weight.

Here is a hack option for measuring without a scale.


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