DIM weight calculator for UPS, FedEx and USPS
Enter your box size and actual weight to see the billable weight the carrier should charge — and whether the package triggers oversize surcharges.
Carrier
Rates
Units
- Dimensional weight
- 14 lb
- Actual weight, rounded up
- 6 lb
Billable weight
14 lb
Charged on dimensional weight
No size-based surcharge should apply to this box.
Check every shipment on your invoice automatically
Carriers re-measure packages and sometimes bill a higher weight than your box warrants. ParcelAudit recomputes the billable weight for every line of your UPS or FedEx invoice and prepares the dispute. First audit free.
Run a free auditWhat is dimensional (DIM) weight?
Carriers charge for the space a package takes, not only its weight. Dimensional weight converts the box volume into pounds: length × width × height in inches, divided by the carrier's DIM divisor. You are billed on whichever is greater — the actual weight rounded up to the next pound, or the dimensional weight.
DIM divisors: UPS, FedEx and USPS
UPS and FedEx use a divisor of 139 for daily and most contract rates, and 166 for retail rates. USPS Ground Advantage and Priority Mail use 166 and apply dimensional weight only to packages larger than one cubic foot. Many contracts negotiate a higher divisor — use yours if you have one.
When DIM weight is billed wrong
Overcharges usually come from automated re-measurement: a scanner reads a bulging or mislabeled box, or a weight correction is applied to the wrong package. If the invoice bills a weight above the correct billable weight of the box you shipped, the difference is refundable. Disputes have deadlines — UPS and FedEx generally allow about 180 days from the invoice date for billing adjustments.
Frequently asked questions
How do I calculate dimensional weight for UPS?
Multiply length × width × height in inches (rounded to the nearest whole inch) and divide by 139 for daily rates or 166 for retail. Round up to the next pound and compare with the actual weight rounded up; UPS bills the greater of the two.
Is the FedEx DIM divisor the same as UPS?
Yes, FedEx also uses 139 for standard rates. Contract customers may have a different divisor, which is shown on the FedEx invoice.
Can I get a refund if I was billed the wrong weight?
Yes. If the billed weight is higher than the correct billable weight of the package as shipped, you can request a billing adjustment from the carrier, usually through its billing portal.