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Dimensional Weight Calculator

Find the dimensional weight and the billable weight of a parcel for UPS, FedEx and USPS, with the current divisor and the carriers' rounding rules.

● Sources checked Oct 13, 20265 primary and carrier sourcesBy FreightClassCheck editorial team

Package

in
in
in
lb

Measure at the widest point of each side. Each carrier rounds the sides its own way; the table shows all three.

Billable weight
CarrierSides used (in)Dim wtBillable
UPS÷139, nearest in18×14×1222 lb22 lb
FedEx÷139, nearest in18×14×1222 lb22 lb
USPS÷139, round up18×14×1222 lb22 lb

US domestic rules as published by each carrier, in inches and pounds; cm and kg are converted first. Rates on your own account can differ: check your agreement.

How dimensional weight works

Parcel carriers charge the greater of the actual weight and the dimensional weight, so a large, light box costs what its size takes on the truck:

  1. Round each side to a whole inch: to the nearest inch for UPS and FedEx, up to the next inch for USPS.
  2. Multiply length × width × height.
  3. Divide by the carrier's divisor and round up to the next pound.
  4. The billable weight is the larger of that and the actual weight, rounded up.

The dim weight formula

dim weight (lb) = length × width × height (in) ÷ 139, any fraction rounded up to a whole pound

Divisors in 2026

CarrierDivisor (in³/lb)Notes
UPS139Daily rates; sides rounded to the nearest inch (UPS rate and service guide, 2025).
FedEx139US, Puerto Rico and international; sides rounded to the nearest inch.
USPS139Since July 12, 2026, sides rounded up; only parcels over one cubic foot; above 70 lb you pay the 70 lb price.

Questions

What is the dim weight divisor for UPS and FedEx?

Both use 139: length × width × height in inches ÷ 139 gives the dimensional weight in pounds. UPS gives 139 for its daily rates; FedEx for US, Puerto Rico and international shipments. Rates on your own account may differ, so check your agreement.

Did USPS change its dimensional weight divisor?

Yes. On July 12, 2026 USPS changed its DIM factor to 139, the same as UPS and FedEx. USPS applies dimensional weight only to parcels larger than one cubic foot (1,728 in³), and above 70 lb of dimensional weight you pay the 70 lb price.

Do carriers round the dimensions?

Yes, but not all the same way. UPS and FedEx round each side to the nearest whole inch (1.49 in counts as 1, 1.50 as 2). USPS has rounded each side up to the next whole inch since July 12, 2026. All three round the dimensional weight up to the next whole pound.

Is volumetric weight the same as dimensional weight?

Yes, it is the same idea under another name: the weight a carrier bills for the space a package takes. Dimensional weight, dim weight and volumetric weight all name the same calculation.

Is dimensional weight the same as freight class?

No. Dimensional weight is how parcel carriers bill packages. LTL freight on pallets is priced by freight class, which comes from density; use the freight class calculator for that.