Shipping
Dimensional Weight Calculator
Enter the outside measurements of your packed box and its actual weight. The calculator works out the dimensional weight and tells you which weight the carrier will bill.
Carriers bill the greater of the box's actual weight and its dimensional weight, which is the space the box takes up converted into pounds. A big, light box can therefore be billed at far more than it weighs on a scale.
Formula
Dimensional weight = (length × width × height in inches) ÷ divisor, rounded up to the next whole pound. Billable weight = the greater of dimensional weight and actual weight. Each side is rounded up to the next whole inch before multiplying.
How it works
Measure the outside of the packed box, longest side first. Each side rounds up to the next whole inch, then the three sides are multiplied and divided by the carrier divisor. Compare that result with the actual weight rounded up: the carrier bills whichever is higher.
Worked example
A 24 × 18 × 12 inch box is 5,184 cubic inches. Divided by 139, that is 37.29 lb, rounded up to 38 lb. The actual weight is 3 lb, so the billable weight is 38 lb — the box is billed at 38 lb even though it weighs only 3 lb on a scale.
FAQs
Why is the divisor 139 and not another number?
139 cubic inches per pound is the published divisor for UPS Daily Rates and for FedEx domestic shipments, and for USPS parcels over one cubic foot since July 12, 2026. UPS Retail Rates (counter prices) use 166 instead, which gives a lower dimensional weight.
Does dimensional weight apply to every parcel?
UPS and FedEx can apply it to any parcel in customer packaging. USPS applies dimensional-weight pricing only to parcels larger than one cubic foot (1,728 cubic inches); smaller USPS parcels are billed by actual weight.
Why are the sides rounded up before multiplying?
Carriers round each measurement up to the next whole inch first, so a 12.2 inch side counts as 13 inches. That rounding alone can raise the billable weight, which is why measuring the packed box exactly matters.
What if my contract has a different divisor?
A negotiated carrier contract can set a different divisor. If yours does, use the UPS Retail Rates option only as a rough guide and confirm your contract divisor with your carrier before quoting prices.
How do I lower a high dimensional weight?
Use the smallest box that protects the item, remove empty space, and avoid oversized outer packaging. Even one inch off each side can drop the billable weight by several pounds.
Stand: October 2026. Divisors: UPS Daily Rates 139 and Retail Rates 166, and FedEx 139, per the carriers' published dimensional-weight pages. USPS 139 for parcels over 1 cubic foot is reported from USPS mailing standards effective July 12, 2026 and is not yet confirmed from a live USPS page in this batch; confirm it with USPS before quoting. Sources: UPS — Shipping Dimensions and Weight, FedEx — About Dimensional Weight.
Disclaimer: Results are estimates and general information only, not tax or financial advice. Your actual fees, shipping costs and profit depend on your marketplace account, category, shipping service and buyer location. Check the figures that apply to you before pricing a listing.
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