FedEx dimensional weight: divisor 139, rules and examples

FedEx bills the greater of actual weight and dimensional weight. Dimensional weight is length × width × height in inches, each rounded to the nearest inch, divided by 139.

The rule

Divisor	139 in³ per lb
Applies	To every size, per the page cited
Each dimension	Rounded to the nearest whole inch
Result	FedEx's page does not say how the result is rounded. Packgent rounds up to the next whole pound, which is the more expensive reading.
Effective	Not stated on the page
Scope	U.S., Puerto Rico and international shipments, as stated on the FedEx page.

DW = ⌈ round(L) × round(W) × round(H) ÷ 139 ⌉
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	4	4	dimensional	H −1 in → 3 lb
12 × 12 × 12	5	12×12×12	1,728	13	13	dimensional	L −1 in → 12 lb
12.4 × 12.4 × 12.4	5	12×12×12	1,728	13	13	dimensional	L −1 in → 12 lb
14 × 10 × 8	4	14×10×8	1,120	9	9	dimensional	L −1 in → 8 lb
16 × 12 × 10	6	16×12×10	1,920	14	14	dimensional	L −1 in → 13 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	100	dimensional	L −1 in → 96 lb
30 × 30 × 30	20	30×30×30	27,000	195	195	dimensional	L −1 in → 188 lb

Try your own box in the calculator.

Other carriers

Source

FedEx: What is dimensional weight?

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

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