USPS Dimensional Weight Calculator
USPS dimensional weight calculator: compare actual weight with DIM weight using the domestic 166 divisor or international 139 estimate.
Type
Frequently asked questions
USPS Dimensional Weight Calculator — Billable Weight
Enter package volume and actual weight to compare USPS dimensional weight with scale weight. The calculator shows which estimate is higher, while the source link and service-specific caveat help you verify the current USPS rules before shipping.
Domestic divisor 166
Models the common domestic DIM-weight estimate shown in the calculator.
International divisor 139
Provides a separate international planning estimate.
Billable-weight comparison
Highlights the higher of dimensional and actual weight.
Worked example: a 12 × 10 × 8 inch package
The package volume is 960 cubic inches. Using the domestic 166 divisor gives 5.78 lb of DIM weight; if the scale weight is 4.2 lb, the higher DIM figure is the planning billable weight.
Domestic estimate: 5.78 lb billable. International divisor 139 would produce about 6.91 lb before service-specific rounding.
How to use this estimate
- 1
Measure the outer box
Use the longest outside dimensions in inches, including packaging that affects the parcel's volume.
- 2
Enter scale weight
Add the actual weight in pounds so the calculator can compare both billing methods.
- 3
Choose the service context
Switch between the domestic 166 planning divisor and the international 139 estimate.
What can change the result
Rounding and packaging
Carriers can round dimensions and weight according to the selected mail class and their measurement rules.
Mail class matters
Not every USPS service applies dimensional weight the same way, especially for unusual package sizes.
Large, light boxes
DIM weight matters most when a parcel takes up more truck or aircraft space than its scale weight suggests.
USPS dimensional-weight treatment can vary by mail class, package size, and destination. Confirm the current service rules before buying postage.
Methodology & sources
This is an independent estimate. The calculator applies the rates shown in its breakdown; platform contracts, country, account tier, taxes, and promotions can change the final amount. Confirm the current terms before making a financial decision.
Rates and platform terms can change. Use the linked official source when available and verify the current terms before transacting.
Example Calculations
| Volume (cu in) | Total Fees | Billable Weight (lbs) |
|---|---|---|
| 100 | $0.00 | $1.00 |
| 500 | $0.00 | $3.01 |
| 1,000 | $0.00 | $6.02 |
| 2,000 | $0.00 | $12.05 |
Based on default settings. Use the calculator above for your exact figures.