01
Round each dimension upward
USPS DMM 123 directs mailers to round length, width, and height to whole inches before multiplying.
CalculatorsFREE · NO SIGNUP
USPS Dimensional Weight Calculator
Apply current USPS domestic dimension rounding, the one-cubic-foot threshold, and the 139 divisor without pretending to quote postage.
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01 USE IT NOW02 NO ACCOUNT03 FIELD NOTES BELOW
WORKING INPUTS
Measure the parcel at its extreme dimensions.
LIVE RESULT
USPS comparison weight
15 lbQualifying domestic DIM comparison only; service, zone, nonstandard fees, and postage are separate.ROUNDED DIMENSIONS18 × 14 × 8 in
ADJUSTED VOLUME2,016 in³
DIM WEIGHT15 lb
ROUNDED ACTUAL WEIGHT10 lb
13
USPS RULES, IN ORDER
Round dimensions before testing the cube.
The threshold and divisor apply after each extreme dimension is rounded up, so fractions can change the result.
WORKING VIEW
15 LB18 × 14 × 8 IN · 10 LB
METHODgreater of rounded actual weight and qualifying DIM weight
WORKING NOTE2,016 in³ exceeds one cubic foot · 15 lb DIM weight
INPUTS → CLEAR OUTPUT
THE FIELD NOTES
Quick answer above. Better decisions below.
Use the result now, then read the practical notes for assumptions, examples, limitations, and the choices behind it.
18 × 14 × 8 IN · 10 LB15 LB
2,016 in³ exceeds one cubic foot · 15 lb DIM weight
02
Test the one-cubic-foot threshold
Domestic Priority Mail DIM pricing applies only when the adjusted volume exceeds 1,728 cubic inches.
03
Use the current 139 divisor
Qualifying adjusted volume divides by 139 and rounds up to a whole pound.
04
Separate weight from postage
Service, zone, nonstandard fees, hazardous-material handling, and other rules can change final postage.
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Round each dimension upward
USPS DMM 123 directs mailers to round length, width, and height to whole inches before multiplying.
Use extreme dimensions for nonrectangular parcels.
Test the one-cubic-foot threshold
Domestic Priority Mail DIM pricing applies only when the adjusted volume exceeds 1,728 cubic inches.
At exactly 1,728 cubic inches, this calculator leaves dimensional weight inactive.
Use the current 139 divisor
Qualifying adjusted volume divides by 139 and rounds up to a whole pound.
The comparison uses the greater of rounded actual weight and dimensional weight, capped at the USPS 70-pound price ceiling for the DIM calculation.
Separate weight from postage
Service, zone, nonstandard fees, hazardous-material handling, and other rules can change final postage.
Use USPS Postage Price Calculator or your label system for the actual price.
Questions, answered.
What USPS dimensional-weight divisor does this use?
It uses 139 for qualifying domestic Priority Mail parcels under the current DMM 123 rule reviewed September 12, 2026.
When does USPS dimensional weight apply?
For this domestic Priority Mail rule, adjusted parcel volume must exceed one cubic foot, or 1,728 cubic inches.
Does this calculator quote USPS postage?
No. It compares actual and dimensional weight; zone, service, surcharges, and current price tables remain separate.
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