USPS dimensional weight: divisor 139, rules and examples

USPS bills the greater of actual weight and dimensional weight. Dimensional weight is length × width × height in inches, each rounded up, divided by 139, and it applies only when the parcel is over 1,728 in³.

The rule

Divisor	139 in³ per lb
Applies	Only when L × W × H exceeds 1,728 in³
Each dimension	Rounded up to the next whole inch
Result	Rounded up to the next whole pound
Cap	If dimensional weight exceeds 70 lb, the 70 lb price applies
Effective	2026-07-12
Scope	Priority Mail (commercial) and Parcel Select, rectangular parcels. Nonrectangular parcels use a 0.785 volume factor and divisor 166.

DW = ⌈ ⌈L⌉ × ⌈W⌉ × ⌈H⌉ ÷ 139 ⌉ if volume > 1,728 in³
billable = max(⌈actual⌉, DW)

Worked examples

Outside, in	Actual, lb	Measured	in³	DW, lb	Billable	Billed on	Cut to save 1 lb
10 × 8 × 6	2	10×8×6	480	n/a	2	actual	—
12 × 12 × 12	5	12×12×12	1,728	n/a	5	actual	—
12.4 × 12.4 × 12.4	5	13×13×13	2,197	16	16	dimensional	L −1 in → 15 lb
14 × 10 × 8	4	14×10×8	1,120	n/a	4	actual	—
16 × 12 × 10	6	16×12×10	1,920	14	14	dimensional	H −1 in → 6 lb
16 × 14 × 10	5	16×14×10	2,240	17	17	dimensional	W −1 in → 15 lb
18 × 12 × 12	8	18×12×12	2,592	19	19	dimensional	L −1 in → 18 lb
20 × 16 × 12	10	20×16×12	3,840	28	28	dimensional	W −1 in → 26 lb
20 × 20 × 20	15	20×20×20	8,000	58	58	dimensional	L −1 in → 55 lb
24 × 18 × 18	20	24×18×18	7,776	56	56	dimensional	W −1 in → 53 lb
24 × 24 × 24	25	24×24×24	13,824	100	70*	dimensional	—
30 × 30 × 30	20	30×30×30	27,000	195	70*	dimensional	—

* capped at the 70 lb price.

Try your own box in the calculator.

Other carriers

Source

USPS Domestic Mail Manual 223 (Priority Mail prices and eligibility), section 1.4
USPS Domestic Mail Manual 253 (Parcel Select prices and eligibility), section 1.2

Last reviewed 2026-10-27. See all sources and how Packgent computes.

Rates and rules change; Packgent re-checks every January and July.