Free shipping tool
Dimensional weight calculator
Carriers bill the greater of actual weight and dimensional (DIM) weight — so a big, light box can cost more than a small, heavy one. Enter your package size to find the billable weight UPS, FedEx, USPS and DHL will charge, then use automated package rules to apply those measurements consistently across every order. No signup required.
USPS
2.0 lb
Under 1 cubic foot: USPS bills actual weight, no dimensional charge
UPS
7.0 lb
Dim: 7.0 lb (divisor 139)
FedEx
7.0 lb
Dim: 7.0 lb (divisor 139)
Tip: Billed weight is the greater of actual and dimensional weight. Reduce any one dimension or use a right-sized box to lower dimensional weight.USPS moved from a 166 divisor to 139 on July 12, 2026 and now rounds every fractional dimension up to the next whole inch, so all four major carriers are on the same divisor. USPS still applies dimensional pricing only above 1 cubic foot.
Dimensional weight FAQ
- What is dimensional weight?
- Dimensional (DIM) weight is a pricing measure that accounts for how much space a package takes up rather than just how heavy it is. A large, light box can cost more to ship than a small, heavy one because it fills trailer and aircraft space that the carrier could otherwise sell. Carriers bill the greater of your package's actual weight and its dimensional weight, so an oversized box gets charged for the room it occupies.
- How do DIM divisors work for UPS, FedEx, USPS and DHL?
- To find dimensional weight you multiply length × width × height in inches and divide by the carrier's DIM divisor. UPS, FedEx and DHL use 139 for domestic shipments. USPS also moved to 139 on July 12, 2026, up from 166, and now rounds every fractional dimension up to the next whole inch. USPS applies dimensional pricing only to packages over 1 cubic foot, which is the one remaining structural difference between the carriers on this charge.
- What is billable weight and how is it calculated?
- Billable weight is the number the carrier actually charges you for — it is the greater of your package's actual weight and its dimensional weight, rounded up to the next pound. Enter your box dimensions and real weight above and the calculator shows the billable weight for each carrier. If dimensional weight is higher than actual weight, you are paying for empty space inside the box.
- Did the USPS DIM divisor change in 2026?
- Yes. On July 12, 2026 USPS lowered its dimensional divisor from 166 to 139 and began rounding each fractional dimension up to the next whole inch. A 12 x 12 x 12 inch box is 1,728 cubic inches: at the old 166 divisor that billed as 11 lb, at 139 it bills as 13 lb. The change applies to Priority Mail Express, Priority Mail, Ground Advantage and Parcel Select on packages over 1 cubic foot. USPS no longer has a divisor advantage over UPS and FedEx; its remaining advantages are the 1-cubic-foot threshold, no residential surcharge, and PO Box delivery.
- How can I lower my dimensional weight charges?
- Use a box that fits the contents snugly — every extra inch in any dimension raises dimensional weight. Cut down oversized cartons, switch to poly mailers for soft goods, and avoid padding the void with bulky filler. Even shaving one dimension can drop you below a billable-weight threshold. Compare live carrier rates with the right box size before you buy the label so the dimensional charge does not surprise you on the invoice.
Know your billable weight? Get a live rate.
Compare live USPS, UPS, FedEx and DHL rates side-by-side with your real box size, then review FedEx vs DHL rate factors or UPS vs DHL billing options before buying discounted labels.