ShipMargin
WeightVerified formula

USPS Dimensional Weight Calculator

Determine whether a US package is billed by actual or USPS dimensional weight.

Free · no sign-upRule: usps-dim-2026.07-v1
Package inputs
Use outside package dimensions. Your result stays on this device unless you choose to save it.
Priority Mail — Commercial
Live result Deterministic
Shipping intelligence
No AI estimates. Every output comes from the published formula.

Your result will appear here

Enter package data and calculate. No account is required.

How to read the result

A decision, not just a number

Apply the current verified USPS Priority Mail commercial DIM rule. Read the result alongside its interpretation, formula version, assumptions, and source. If a carrier rule is not verified, the production result remains disabled.

Worked example

Example calculation

A rectangular 18 × 14 × 10 in parcel exceeds one cubic foot and is divided by 139 after USPS dimension rounding.

Assumptions

  • • US domestic Priority Mail commercial rules and Zones 1–9.
  • • Measurements are rounded up to whole inches.

Limitations

  • • This does not calculate postage or contract rates.
  • • Other mail classes can have distinct eligibility rules.

Frequently asked questions

Is the USPS Dimensional Weight Calculator free?

Yes. Core ShipMargin calculators are free and show results without requiring an account.

Does this calculate a shipping price?

No. Without a verified live rate source, ShipMargin reports deterministic weights, dimensions, fit, or margin metrics—not invented dollar savings.

Can I save the result?

Anonymous results can be copied or shared. Saving calculation history is an optional account feature once Supabase is configured.