Dimensional Weight Calculator
Find the dimensional (DIM) weight and billable weight of a parcel in seconds. Enter the size and actual weight, pick a carrier divisor, and see whether size or scale weight sets your price.
Dimensional Weight Calculator
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How it works
Carriers sell space as well as weight. A pillow weighs almost nothing but fills a lot of truck, so carriers compare the scale weight with a size-based weight and bill the greater of the two. That size-based number is the dimensional weight.
The divisor is the carrier’s rule for how much volume counts as one pound. A lower divisor means a higher dimensional weight. For U.S. domestic parcels, UPS and FedEx publish a divisor of 139 cubic inches per pound. Published guidance reports that USPS moved from 166 to 139 on July 12, 2026 for Priority Mail, Ground Advantage and Parcel Select, and began rounding fractional inches up. Contracts can differ, so check your rate agreement.
Billable weight = greater of actual weight and dimensional weight
Worked example
Example: A 14 × 12 × 15 in box weighing 6 lb.
Volume = 2,520 in³. At ÷139 the dimensional weight is 18.13 lb, rounded up to 19 lb. The scale says 6 lb, so you are billed for 19 lb.
At the older ÷166 divisor the same box would be 15.18 lb, rounded to 16 lb.
Tips to save money
- Measure the longest point on each side including any bulging. Carriers measure the finished package, not the product.
- Right-size the box. Trimming just one inch from each dimension of a 14 × 12 × 15 in box cuts its volume by about 21%.
- Use poly mailers for soft goods that can compress.
- Negotiate the divisor if you ship high volume; some contracts specify a higher divisor than the published one.
Frequently asked questions
What is dimensional weight?
Dimensional weight, also called DIM weight or volumetric weight, is a size-based weight calculated from a package’s length, width and height. Carriers charge for whichever is greater: the dimensional weight or the actual scale weight.
What DIM divisor do UPS, FedEx and USPS use?
UPS and FedEx publish 139 in³/lb for most U.S. domestic services. USPS was reported to move from 166 to 139 on July 12, 2026 for its main parcel products. Some international services and negotiated contracts use 166 or metric divisors such as 5,000. Always confirm on the carrier’s site or in your contract.
Does every package get dimensional weight pricing?
Not always. Carriers apply thresholds and exceptions that differ by service, and some only apply DIM weight above roughly one cubic foot. Check the rules for the exact service you use.
How is dimensional weight rounded?
Many carriers round each dimension up to the next whole inch and then round the final weight up to the next pound. This calculator does both by default; you can switch rounding of dimensions off to see the raw figure.
Are dimensional weight and volumetric weight the same?
Yes. “Dimensional weight” is the common U.S. term, while “volumetric weight” is more common in the UK, Canada, Australia and for international shipping. Try the volumetric weight calculator for metric units.
Related calculators
Results are estimates for planning. Carriers may measure, round and bill differently, and rules change. Confirm the divisor, rounding and surcharges with your carrier or contract before relying on a figure.