DimWeight Calc › USPS
USPS dimensional weight calculator
USPS only charges dimensional weight on parcels over 1 cubic foot (1,728 in³) going to Zones 1–9. Enter the box and an optional ship date: the rule changed on July 12, 2026.
Calculations run entirely in your browser – the sizes and weights you type are never sent to a server.
USPS dimensional weight rules
USPS Priority Mail Express, Priority Mail, Ground Advantage, Parcel Select (retail & commercial) – from Jul 12, 2026
| Formula | If L × W × H (in) [× 0.785 if non-rectangular] > 1,728: ÷ 139 = lb |
|---|---|
| Rounding | Each side rounded up to the nearest whole inch (DMM 604.7.0); dimensional weight rounded up to the next whole lb. Above 70 lb the 70 lb price applies. |
| Applies to | Only parcels to Zones 1–9 whose volume exceeds 1 cubic foot (1,728 in³). Non-rectangular parcels: volume × 0.785 first. |
| Effective | From July 12, 2026 (DMM changes marked [7-12-26]; Postal Bulletin 22705). |
- Zones 1–9 only.
Sources (checked ):
- USPS DMM 123 – Priority Mail (retail) [P1, official]
- USPS DMM 113 – Priority Mail Express (retail) [P2, official]
- USPS DMM 213 – Priority Mail Express (commercial) [P2, official]
- USPS DMM 223 – Priority Mail (commercial) [P3, official]
- USPS DMM 253 – Parcel Select [P4, official]
- USPS DMM 283 – Ground Advantage (commercial) [P4, official]
- USPS Postal Bulletin 22705 [P5, official]
- USPS Ground Advantage [P6, official]
USPS Commercial Priority Mail – non-rectangular (DMM 223 text as published)
| Formula | L × W × H (in) × 0.785; if > 1,728: ÷ 166 = lb |
|---|---|
| Rounding | Each side rounded off (nearest whole inch); dimensional weight rounded up to the next whole lb. |
| Applies to | Commercial Priority Mail, non-rectangular parcels to Zones 1–9 over 1,728 in³ (after × 0.785). |
| Effective | Current DMM 223 text; this paragraph has no [7-12-26] mark. Whether USPS actually bills this way could not be verified. |
- DMM 223 still says ÷166 and “round off” for non-rectangular parcels, unlike the rectangular rule on the same page (139, round up) and the other DMM chapters. It may be an oversight by USPS; we follow the published text.
Not verified: Whether USPS applies 166 / round off in practice. Treat these as adjustable settings.
Sources (checked ):
- USPS DMM 223 – Priority Mail (commercial) [P3, official]
USPS – rule before Jul 12, 2026
| Formula | If L × W × H (in) [× 0.785] > 1,728: ÷ 166 = lb |
|---|---|
| Rounding | Each side rounded off to the nearest whole inch; dimensional weight rounded up to the next whole lb. |
| Applies to | Ship dates before July 12, 2026; Zones 1–9, over 1,728 in³. |
| Effective | Until July 11, 2026. |
Sources (checked ):
- USPS DMM 123 archive (rule before Jul 12, 2026) [P7, official]
- USPS QSG 150 archive (Jul 13, 2025 – old rule: ÷166) [P8, official]
Worked examples
- Box 12.2 × 10 × 10 in: sides round up to 13 × 10 × 10 = 1,300 in³ – not over 1,728, so no dimensional weight; you pay for the actual weight.
- Box 21 × 20 × 20 in, 10 lb, shipped on or after July 12, 2026: 8,400 ÷ 139 = 60.43 → 61 lb.
- Same box shipped before July 12, 2026 (old rule ÷166): 50.6 → 51 lb.
- Non-rectangular parcel 20.4 × 20 × 20 in, Commercial Priority Mail under the DMM 223 text: sides round off to 20 × 20 × 20, × 0.785 = 6,280 in³, ÷ 166 = 37.83 → 38 lb. Under the 2026 rule used elsewhere (round up, ÷139): 6,594 in³ → 48 lb.
FAQ
When does USPS charge dimensional weight?
Only for parcels to Zones 1–9 whose volume, after rounding each side, is more than 1,728 cubic inches (1 cubic foot). Exactly 1,728 in³ is not charged dimensional weight.
What changed on July 12, 2026?
The divisor changed from 166 to 139 and each side is now rounded up to the next whole inch instead of to the nearest inch (DMM changes marked [7-12-26]).
How are non-rectangular parcels handled?
Multiply length × width × height by 0.785 first. DMM 223 (Commercial Priority Mail) still says round off and divide by 166 for non-rectangular parcels; the calculator follows that text when you pick Commercial Priority Mail and Non-rectangular, and says so.
What if the dimensional weight is over 70 lb?
USPS charges the 70-pound price. A parcel whose actual weight is over 70 lb is not accepted.