US Postal Service now requires shipping labels to include exact parcel dimensions

The Postal Service is tightening rules for how packages are shipped — shippers must now list accurate dimensions on every parcel manifest, not just weight. This means sorting machines can route packages more efficiently, and packages that don't match their declared size get caught before they reach the network instead of jamming equipment downstream.

For decades, the Postal Service sorted mail by weight and barcode alone, which meant oversized parcels got routed wrong and created bottlenecks at sorting facilities and on delivery trucks. Requiring dimensional data forces shippers to be honest about what they're sending and gives the Post Office real information to automate routing decisions. The practical effect is simpler: accurate dimensions reduce jam-ups in the sorting system and lower the cost of handling each parcel.