350 cubic inches (0.2 cu ft, 0.0057 m³). Often used for books, small kits.
Packed lighter than this, you are billed this weight anyway.
| Carrier | Divisor | DIM weight |
|---|---|---|
| USPS | 139 | actual weight |
| UPS (Daily Rates) | 139 | 3 lb |
| FedEx | 139 | 3 lb |
| UPS (Retail Rates) | 166 | 3 lb |
| DHL Express (International) | 5000 | 1.5 kg |
Stepping down to a 12 × 9 × 3 in box drops the UPS and FedEx floor to 3 lb.
At or under 1 cubic foot, USPS bills actual weight, as long as no side rounds up past the line.
Your box Rounded up by USPSWhole numbers, nothing rounded
Sample box shown. Type your own size and weight below; the result updates instantly.
USPS · divisor 139
Priority Mail, Priority Mail Express, Ground Advantage, Parcel Select
Billable weight
1lb
Under 1 cubic foot: USPS bills actual weight.
| USPS | ÷139 | 1 lb |
| UPS | ÷139 | 3 lb |
| FedEx | ÷139 | 3 lb |
| UPS Retail | ÷166 | 3 lb |
| DHL Express | ÷5000 | 1.5 kg |
350 cubic inches ÷ 139 = 2.52, rounded up to 3 lb for UPS Daily Rates and FedEx. USPS bills actual weight because the box is not larger than 1 cubic foot.
With UPS and FedEx, anything packed under 3 lb is billed as 3 lb. Above that, you pay actual weight.
Carrier rules verified 2026-09-30. Methodology