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Dimensional Weight Calculator

DIM weight and billable weight for one carrier at a time: UPS, FedEx, USPS, express or air freight. To rank every carrier at once, use the comparison calculator.

Updated · By Niraj Kumar

How is dimensional weight calculated?

Multiply the box's length × width × height in inches, then divide by 139 for UPS and FedEx. A 12 × 12 × 12 in box is 1,728 in³ ÷ 139 = 12.43, billed as 13 lb. International express carriers use centimetres ÷ 5000, and air cargo ÷ 6000. You pay whichever is higher: DIM or actual weight.

Carriers charge for the space a package takes as well as its weight. The box's volume divided by the carrier's divisor gives a dimensional weight, and you pay for whichever is higher, that or the actual weight. UPS, FedEx and USPS round each fractional inch up and bill whole pounds, and USPS only applies DIM above one cubic foot; air cargo works in centimetres and bills in half-kilogram steps.

DIM weight = length × width × height ÷ divisor; billable = max(actual, DIM)
139
UPS, FedEx and USPS, inches and pounds
1,728 in³
One cubic foot: USPS bills actual weight at or below it
5000
International express, centimetres and kilograms
6000
IATA air freight, centimetres and kilograms

Worked example

An 18 × 14 × 12 in box weighing 8 lb, shipped UPS Ground.

  1. 1Volume: 18 × 14 × 12 = 3,024 in³
  2. 2DIM weight: 3,024 ÷ 139 = 21.8, rounded up to 22 lb
  3. 3Actual weight: 8 lb
  4. 4Billable: the greater of 22 and 8

Billed as 22 lb, 14 lb more than the box actually weighs.

Frequently asked questions

Does dimensional weight apply to every package?

UPS and FedEx apply it to all ground and air packages. USPS applies it to Priority Mail and Ground Advantage parcels over one cubic foot (1,728 in³), with the same 139 divisor since 12 July 2026. Air cargo and international express always use volumetric weight. Small, dense packages are almost never affected.

How do I lower dimensional weight?

Use the smallest box the product fits in with adequate padding. A single inch off each side of an 18 × 14 × 12 box cuts DIM weight by about 20%. Poly mailers suit soft goods, and high-volume shippers can negotiate a higher divisor, such as 166 or 194 instead of 139, which lowers DIM weight on every package.

What is the difference between 5000 and 6000 divisors?

Express couriers such as DHL Express, UPS Worldwide and FedEx International divide cubic centimetres by 5000, which gives a higher volumetric weight. Airlines and freight forwarders use the IATA standard of 6000. The same box can therefore bill 20% heavier by express courier than as air cargo.

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