Shipping box and dimensional weight calculator
Carriers bill the larger of actual weight and dimensional weight. Enter your box size and packed weight to see the billed weight for UPS and USPS, compare boxes for your kits, and spot boxes that ship mostly air.
Billed weight
Enter a box size and packed weight to see the billed weight.
Dimensional weight divisors in 2026
| Carrier and rate | Divisor | When it applies | Rounding |
|---|---|---|---|
| UPS daily rates | 139 | All packages | Fractional inches round up (since Aug 18, 2025) |
| UPS retail rates | 166 | All packages | Same |
| USPS (Priority Mail, Ground Advantage, Priority Mail Express, Parcel Select) | 139 | Packages over 1 cubic foot (1,728 cubic inches) | Fractional inches round up (since Jul 12, 2026) |
| FedEx | 139 for most services | All packages | Check your account |
Billed weight for common box sizes
| Box | Volume | UPS daily billable | USPS billable |
|---|---|---|---|
| 9 x 6 x 3 | 162 cu in | 2 lb | 2 lb |
| 10 x 8 x 4 | 320 cu in | 3 lb | 2 lb |
| 12 x 9 x 4 | 432 cu in | 4 lb | 2 lb |
| 12 x 12 x 6 | 864 cu in | 7 lb | 2 lb |
| 14 x 10 x 6 | 840 cu in | 7 lb | 2 lb |
| 16 x 12 x 8 | 1,536 cu in | 12 lb | 2 lb |
| 18 x 14 x 8 | 2,016 cu in | 15 lb | 15 lb |
| 20 x 16 x 12 | 3,840 cu in | 28 lb | 28 lb |
How to lower shipping cost on kits
- Choose the smallest box that protects the contents.
- Use mailers or poly bags for kits that are apparel only.
- Avoid fractional inches: carriers round each side up to the next whole inch.
- Pack apparel flat and folded.
- When you can, ship in bulk to one address and kit locally.
Frequently asked questions
- What is dimensional weight?
- Dimensional weight is a weight carriers calculate from a package's size. A large, light box takes up truck space, so the carrier bills it as if it were heavier.
- How is dimensional weight calculated for UPS?
- Length x width x height in inches, each rounded up to the next whole inch, divided by 139 for daily rates or 166 at retail.
- Did USPS change dimensional weight in 2026?
- Yes. From July 12, 2026, USPS uses a 139 divisor for packages over 1 cubic foot and rounds fractional inches up.
- Which weight does the carrier charge?
- The larger of actual weight and dimensional weight.
- How can we reduce dimensional weight?
- Use smaller boxes, whole inch box sizes and mailers for soft goods.
Sources
Verified October 2026.