A lower divisor bills more weight
The divisor turns volume into pounds. Dividing by 139 gives more pounds than dividing by 166, so a 139 carrier bills a bulky box heavier than a 166 carrier does.
Dimensional weight divisors by carrier
Every divisor, rounding rule and applicability note the calculators on this site use, in one table, with the source for each row. This is the dataset behind the dimensional weight calculator and the four carrier pages.
The divisor dataset
| Carrier or program | Imperial divisor | Metric divisor | Rounding | Applies to | Source |
|---|---|---|---|---|---|
| FedEx | 139 in³/lb | 5,000 cm³/kg | Each side up to the next whole inch; DIM up to the next whole lb | All packages in customer packaging; U.S., Puerto Rico and international | FedEx Service Guide 2026 |
| UPS Daily Rates | 139 in³/lb | 5,000 cm³/kg | Each side up to the next whole inch; fraction of a lb up | Daily-rate (account) shipments, domestic and international; also retail export | UPS Rate and Service Guide 2026, Daily Rates |
| UPS Retail Rates | 166 in³/lb | 6,000 cm³/kg | Each side up to the next whole inch; fraction of a lb up | Retail (counter) rates, domestic shipments | UPS Rate and Service Guide 2026, Retail Rates |
| USPS | 139 in³/lb | — | Each side up per DMM 604.7.0; DIM up to the next whole lb; 70-lb price cap | Parcels over 1,728 in³ only: Priority Mail Express, Priority Mail, Ground Advantage, Parcel Select; retail and commercial; Flat Rate exempt | USPS DMM 223.1.4 and parallels |
| DHL Express | 139 in³/lb | 5,000 cm³/kg | Per piece, per the service guide | Express services from the United States | DHL US Service and Rate Guide 2026 |
| UPS labels via Pirate Ship | 166 in³/lb | — | Per UPS rules | UPS Ground and 3 Day Select labels bought through Pirate Ship; DIM only over 1 cu ft | Pirate Ship published help pages |
USPS per service: Priority Mail Express (DMM 113.1.4 / 213.1.4), Priority Mail (123.1.4 / 223.1.4), Ground Advantage (133.1.4 / 283.1.4) and Parcel Select all state the same rule — parcels exceeding 1 cubic foot are billed on the greater of actual or dimensional weight at divisor 139, in retail and commercial sections alike.
How to read this table
The program matters, not just the carrier
UPS has two divisors because it sells two rate types. A label platform can run its own program on top of a carrier's network, as the Pirate Ship row shows. Check the row that matches how you bought the label.
Rules move
USPS changed its divisor on July 12, 2026, and UPS and FedEx changed their rounding on August 18, 2025. Pages written before those dates teach the old rules. Our methodology page describes how this table is rechecked.
Sources
- UPS Rate and Service Guide 2026, Daily Rates and Retail Rates
- FedEx Service Guide 2026 (effective January 5, 2026)
- USPS Domestic Mail Manual, dimensional weight sections and 604.7.0
- DHL US Service and Rate Guide 2026
- Pirate Ship published help pages on dimensional weight pricing
Rules last checked November 12, 2026 · How we check every figure