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Dimensional weight calculator

Billable weight for UPS, FedEx and USPS boxes.

Quick answer

DIM weight = length × width × height (in) ÷ 139 for UPS daily rates, FedEx and USPS (from July 12, 2026). Carriers bill the higher of DIM and actual weight.

Start from an example:

Carrier

Rate type
USPS only uses DIM weight for boxes over 1 cubic foot.
Used when Custom is selected. Check your contract.

Box

in
in
in
lb

Published list divisors as of 2026. Negotiated contracts and some services differ; check your carrier account.

How dimensional weight is calculated

  • Round each side up

    12.2 × 10.8 × 6.1 in → 13 × 11 × 7 in

    UPS, FedEx and USPS round each measurement up to the next whole inch before calculating.

  • Divide by the divisor

    L × W × H ÷ 139 (or 166)

    139 for UPS daily rates, FedEx and USPS. UPS retail rates use 166. Round the result up to the next pound.

  • Bill the higher weight

    max(DIM weight, actual weight)

    Light, bulky boxes bill on DIM weight. USPS applies DIM weight only to boxes over 1 cubic foot (1,728 cu in).

Frequently asked questions

What is the USPS dimensional weight divisor in 2026?

139, from July 12, 2026. It was 166 before. It applies to Priority Mail, Ground Advantage and Parcel Select boxes over 1 cubic foot.

What divisor do UPS and FedEx use?

139 for UPS daily rates and FedEx. UPS retail rates (at a UPS Store) use 166.

How do I lower my DIM weight?

Use the smallest box that fits, cut empty space, and try poly mailers for soft items.

What about metric?

In centimeters and kilograms, most carriers divide by 5,000.

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Updated ·By the Deviantly data team

Sources: DCL Logistics: USPS DIM weight changes, July 12, 2026 · Optioryx: How to calculate dimensional weight in 2026