Heavy shipments or shipments that are large in size are typically more expensive to transport. You might have noticed this when creating postage for your shipments. Dimensional weight or volumetric weight, is a measurement that carriers use to relate a shipment’s size to its actual weight or scale weight. It is a common industry practice for carriers to calculate postage based on the greater of the two: actual weight or dimensional weight.


For example, imagine a very light shipment that is packaged in a large box. The shipment’s actual weight may be 2 lbs but due to the dimensions of the large box, its dimensional weight may be 5 lbs. In this case, the carrier would calculate the postage using the dimensional weight of 5 lbs.


How is dimensional weight calculated?


Carriers calculate dimensional weight using a specific formula. To calculate dimensional weight, you will need to know the dimensions of your shipment (length, width and height) and the divisor used by the carrier. This divisor is a standard set by each carrier.



Dimensional weight is used to calculate the correct postage rate for the shipments you create on the Chit Chats platform. Specifically, dimensional weight will apply to following postage types:



  • USPS Priority Mail, Priority Mail Express and Parcel Select*

  • UPS Mail Innovations Parcel Select*

  • Chit Chats Canada Tracked

  • Chit Chats International Standard*


There may also be maximum weights and dimensions for the services you choose. Dimensional weight may also apply to your shipment delivery fees.


For this reason it is important to be mindful of how you package your shipments. It is expensive to ship air, so make sure to package your shipments as small as possible. You should also take care to accurately report the weight and dimensions of your shipment. This will help you to avoid an issue with insufficient postage like a postage adjustment.


*Some services may only be available for grandfathered accounts.