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 (10 inches by 10 inches by 10 inches). The shipment’s actual weight may be 3 lbs but due to the dimensions of the large box, its dimensional weight may be 6.02 lbs. In this case, the carrier would calculate the postage cost using the dimensional weight of 6.02 lbs.
US & International: 
Canada:
Dimensional weight is used to calculate the correct postage rate for the shipments you create on the Chit Chats platform.
It’s also important to understand how both the actual weight and the dimensional weight of your shipment impact your postage. As most carriers enforce maximum weights and dimensions for many services, if the dimensional weight of your shipment exceeds the limit for a particular service, you will not be able to receive a postage rate for that service. For this reason it is important to be mindful of how you package your shipments and use packaging that is suitable for the size and contents of the shipment. 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.
Surcharges may apply for oversized and irregular shipments.