Free tool
Dimensional weight calculator
Enter your box size and the parcel’s actual weight. The calculator shows the dimensional weight and the weight you will be billed for.
How dimensional weight works
Carriers bill the greater of a parcel’s actual weight and its dimensional weight. Dimensional weight is the parcel’s volume divided by a number the carrier sets, called the divisor. For US domestic services from UPS and FedEx the divisor is commonly 139 cubic inches per pound, so a 12 × 9 × 6 inch box (648 cubic inches) is billed at no less than 5 lb, even if it holds a 1 lb item. Divisors change, so check your carrier’s current rate guide before relying on a figure.
That is why a box one size too big can cost more in freight than it saves in unit price. The table shows the dimensional weight of our stock cartons.
| Stock carton (inches) | Cubic inches | At 139 | At 166 |
|---|---|---|---|
| 5.9 × 5.9 × 5.9 | 206 | 2 lb | 2 lb |
| 9 × 6 × 6 | 323 | 3 lb | 2 lb |
| 12 × 9 × 6 | 648 | 5 lb | 4 lb |
| 15 × 12 × 9 | 1,624 | 12 lb | 10 lb |
| 18 × 12 × 12 | 2,594 | 19 lb | 16 lb |
| 20 × 16 × 12 | 3,839 | 28 lb | 24 lb |
Rounded up to the next whole pound, as carriers do. Dimensions are internal; carriers measure the outside of the packed parcel, which is slightly larger.
Questions
What is dimensional weight?
The billable weight a carrier calculates from a parcel’s size: length × width × height divided by a carrier divisor. You are billed on whichever is greater, the actual weight or the dimensional weight.
Which divisor should I use?
Use the one in your carrier’s current rate guide. 139 cubic inches per pound is common for UPS and FedEx domestic services, 166 for USPS parcels over one cubic foot, and 5,000 cubic centimetres per kilogram is common internationally.
How do I lower my dimensional weight?
Use a smaller box. Measure the product, add only the padding it needs, and choose the smallest carton that fits; the box size finder does this for our stock sizes. For soft goods, a mailer has no fixed volume and is often cheaper to ship.
Does the calculator include carrier surcharges?
No. It calculates billable weight only. Surcharges for oversize, residential delivery or fuel are set by the carrier.