USPS dimensional weight now divides by 139, not 166, and rounds sides up
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USPS dimensional weight now divides by 139, not 166, and rounds sides up
Since July 12, 2026, Priority Mail Express, Priority Mail, Ground Advantage and Parcel Select boxes over 1,728 cubic inches (1 cubic foot) are billed at the greater of actual weight or dimensional weight, and dimensional weight is now length x width x height divided by 139 instead of 166. Each side is also rounded up to the next whole inch instead of to the nearest inch. A 16 x 12 x 12 in. box now bills as 17 lb instead of 14 lb.
Your net on a $10 / $25 / $50 sale: -$1.24 / -$1.24 / -$1.24
Commercial Ground Advantage, 16 x 12 x 12 in. box weighing 5 lb, Zone 1: billed at 17 lb ($17.02) instead of 14 lb ($15.78) at Oct 4 prices (the same $1.24 at July 12, 2026 prices). Zone 5: -$2.13; Zone 8: -$3.89. A 12 1/4 in. cube weighing 5 lb: -$6.34 commercial, Zone 1, at peak prices (-$5.94 at July 12, 2026 prices; USPS hasn't published the prices that follow Jan 17, 2027).
Source: USPS final rule, Federal Register, May 15, 2026 (+ DMM 133 Jan 18 vs Jul 12, 2026) · verified
Cite this
The Reseller Index change tracker, "USPS dimensional weight now divides by 139, not 166, and rounds sides up," https://resellerindex.com/changes/usps/2026-07-12-usps-dim-divisor-139/, verified Oct 14, 2026. Free to reuse with a link (CC BY 4.0).
More USPS changes
- USPS holiday prices: Ground Advantage up $0.40 to $0.75 on 0-3 lb parcels
- USPS holiday ship-by dates: Ground Advantage Dec. 17, Priority Mail Dec. 18
- USPS may raise stamp and Media Mail prices in January 2027, by up to 2.105% on average per class
- Light parcels hit hardest: commercial Ground Advantage drops its ounce tiers
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