Understanding USPS Girth Constraints
About Girth Calculations
For parcels, length is the measurement of the longest dimension and girth is the distance around the thickest part (perpendicular to the length).
Except for USPS Retail Ground and Parcel Select, no mail-piece may measure more than 108 inches in length and girth combined.
When shipping USPS with ShipHero, the limit on our shipment endpoint is 108" (length+girth) restriction as required by USPS.
Beyond these limits, there are further restrictions on a country-by-country basis.
For example, Russia has a (length+girth) restriction of 79" for Priority International Parcels.
Due to an integration constraint with USPS, individual country restrictions can only be validated when generating a label. This means you will see a rate, but get an error when generating the label.