ShipMargin
Working tool + original analysis

Dimensional Weight vs Actual Weight

Compare physical weight with the space a parcel occupies in a carrier network.

Free · no sign-upRule: generic-dim-v1
Package inputs
Use outside package dimensions. Your result stays on this device unless you choose to save it.
Generic DIM scenario
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.

Two measurements, one billable result

Actual weight comes from the scale. Dimensional weight comes from package volume and a rule-specific divisor. A verified rule compares them and uses the greater value as billable weight.

A worked decision

If a 5.2 lb parcel produces 9 lb DIM weight, billable weight is 9 lb. ShipMargin reports a 73% DIM penalty: (9 − 5.2) ÷ 5.2 × 100.

  1. 1Confirm outside package dimensions
  2. 2Select a verified rule or transparent generic scenario
  3. 3Compare actual and DIM weight
  4. 4Investigate a tighter box when DIM weight wins

What the number does not tell you

Billable weight is not a postage quote. Zone, service, account terms, minimums, and surcharges can still change the final price.

Reviewed source

USPS Domestic Mail Manual 223.1.4

Last reviewed: August 31, 2026