Shipping and packaging calculators
The rules carriers actually bill by, applied exactly: dimensional divisors and thresholds, USPS cubic tiers with the quarter-inch round-down, pallet patterns with height and weight limits, and the box that keeps your billable weight down.
- Dimensional Weight Calculator (USPS, UPS, FedEx)Billable weight for all three carriers at once, with the 2026 divisors and rounding rules.
- USPS Cubic Pricing CalculatorEligibility and cubic tier for boxes and soft packs, rounded down to the quarter inch the way USPS does.
- Pallet Calculator — boxes per palletBoxes per layer and per pallet with column and mixed patterns, height and weight limits, and a diagram.
- Box Size CalculatorThe smallest stock box that fits your item with padding, and what it does to dimensional weight.
Which tool answers which question
| Your question | Tool | Rule it applies |
|---|---|---|
| What weight will the carrier bill for this box? | Dimensional weight | USPS 139 above one cubic foot; UPS 139 (daily) or 166 (retail); FedEx 139 |
| Is it cheaper at USPS cubic prices, and what does it cost? | USPS cubic | Sides rounded down to ¼ inch; 0.1 cubic-foot tiers; Notice 123 prices by zone |
| What is the smallest box that fits this item? | Box size | Six orientations, your padding, dimensional weight of each box |
| How many cartons go on a pallet? | Pallet | Column and mixed patterns; height and weight limits |
Start with the box
Most overcharges begin with the packaging. A 2 lb item in a 12 × 12 × 8 box is billed at 9 lb by UPS and FedEx; in a 10 × 8 × 6 box it is billed at 4 lb. Pick the box first, check its dimensional weight across the three carriers, then see whether USPS cubic pricing beats the weight-based price. For wholesale and FBA shipments, the pallet calculator plans the layer and shows whether height or weight limits you first.
2026 changes that catch sellers out
- USPS moved its dimensional divisor from 166 to 139 on 12 July 2026, raising dimensional weight on oversize parcels by about 19%.
- USPS cubic price tables in Notice 123 took effect on 4 October 2026.