Calculates the dimensional weight and other key metrics for a package.
Shipping rates are determined by the dimensional weight ("billing weight") when it exceeds the scale weight (FedEx and UPS).
USPS only charges the dimensional weight for domestic Priority Mail shipments when the package volume exceeds
one cubic foot and the destination is to zones 5-9. Other dimension based surcharges may apply if the package
exceeds certain length plus girth thresholds. This calculator will determine the billing weight and/or the applicable
FedEx and UPS may have other surcharges when packages exceed certain (very large) dimensions but this calculator
does not account for those at this time