What is the surcharge that may be applied to priority parcels?

Dimensional weight is a pricing technique that takes into account the density of a package. It is used to ensure that the shipping charge reflects the space a package occupies on a delivery vehicle rather than just its actual weight. In the case of Priority Mail parcels, if the dimensional weight calculated from the package's dimensions exceeds the actual weight, the dimensional weight may be used to determine the shipping cost. This means that the surcharge based on dimensional weight could potentially increase the shipping fee for large but lightweight packages, emphasizing the importance of considering both dimensions and weight when shipping.

The other options, while related to shipping fees, do not directly pertain to additional charges based on size and weight calculations in the same way that dimensional weight does. Flat Rate refers to a set price for specific shipping services regardless of weight, handling fees relate to service requirements rather than size, and delivery charges are general fees for the delivery service rather than surcharges based specifically on dimensional considerations.