The U.S. Postal Service will change shipping prices on January 27, 2019, but expand dimensional-weight pricing on a separate schedule: June 23. Its January 23 notice delays the new size-based rules for retail and commercial Priority Mail and Priority Mail Express, and commercial Parcel Select. A small business updating its shipping software therefore has two implementation dates to keep apart. [S1]

Existing dimensional pricing is not going away in the meantime. USPS says the current provisions for retail and commercial Priority Mail in zones 5–9 will remain on January 27. It will, however, eliminate balloon pricing for Priority Mail in zones 1–4 and commercial Parcel Select across all zones and entries. The June delay is not a reason to leave every January setting unchanged. [S1]

First-Class Package Service also changes in January: prices will depend on both weight and postal zone, rather than weight alone. The October 2018 final rule applies that change to retail and commercial service. For a shop calculating shipping charges, product weight alone will no longer supply every pricing input; the destination zone matters too. [S1][S2]

For the planned June change, consider a rectangular Parcel Select box. The final rule applies dimensional pricing to Ground and Destination Entry parcels sent to zones 1–9 when volume exceeds one cubic foot, or 1,728 cubic inches, charging on the greater of actual and dimensional weight. The rectangular formula multiplies the dimensions, rounded to whole inches, divides the qualifying volume by 166 and rounds up to a whole pound. An illustrative 18-by-12-by-10-inch box occupies 2,160 cubic inches, giving a dimensional weight of 14 pounds. If the box actually weighs five pounds, the planned formula would price it at the 14-pound weight. That is chargeable weight, not a dollar postage quote. [S1][S2]

The October rule names January 27 as its effective date, so reading that document alone would put the new dimensional calculation on the wrong schedule. USPS’s later January notice moves those provisions to June 23 without postponing the January price changes. Shipping-system updates need to preserve that distinction. [S1][S2]

Source documents

  1. New prices — USPS to implement changes Jan. 27https://news.usps.com/2019/01/23/new-prices-5/
  2. Domestic Competitive Products Pricing and Mailing Standards Changes — final rule, 83 FR 52326https://www.govinfo.gov/content/pkg/FR-2018-10-17/html/2018-22474.htm