20x20x20 box dimensional weight

8,000 cubic inches (4.63 cu ft, 0.1311 m³). Often used for moving box, large bulky goods.

Billable weight floor by carrier

Packed lighter than this, you are billed this weight anyway.

Stepping down to a 24 × 18 × 16 in box drops the UPS and FedEx floor to 50 lb, 8 lb less per parcel.

This box is over 1 cubic foot, so USPS applies dimensional weight.

Your box Rounded up by USPSWhole numbers, nothing rounded

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USPS · divisor 139

Priority Mail, Priority Mail Express, Ground Advantage, Parcel Select

Billed on dimensions

Billable weight

58lb

You pay for 35 lb of air on every box.

A box 1 inch smaller on every side bills 8 lb less.

What is the dimensional weight of a 20x20x20 box?

8,000 cubic inches ÷ 139 = 57.55, rounded up to 58 lb for UPS Daily Rates and FedEx. USPS also bills 58 lb since the July 2026 change.

How heavy does a 20x20x20 box need to be to avoid DIM charges?

With UPS and FedEx, anything packed under 58 lb is billed as 58 lb. Above that, you pay actual weight.

Carrier rules verified 2026-09-30. Methodology