Enter your box dimensions and actual weight to instantly see your DIM weight and whether FedEx, UPS, USPS, or DHL will bill you on dimensional or actual weight. Supports imperial and metric.
Calculate DIM weight and billable weight for parcel shipments across major carriers
DIM weight = (L × W × H) ÷ divisor, rounded up. FedEx and UPS use 139 (imperial) or 5,000 (metric). USPS uses 166. If DIM weight > actual weight, you're billed on DIM.
Carriers have limited truck and plane capacity. A large, lightweight box takes up space that could hold heavier, denser freight. DIM pricing ensures carriers are compensated for the cubic space a package occupies.
The single best way to avoid DIM charges is to use the smallest box that safely protects your product. Every extra inch of headspace in a box adds to your billable weight at the 139 divisor.
High-volume shippers can negotiate a custom DIM divisor above 139 with FedEx and UPS. A divisor of 166 (USPS rate) or higher means your packages need to be significantly larger before DIM billing kicks in.
| Carrier | Service | Imperial Divisor | Metric Divisor | Applies to |
|---|---|---|---|---|
| FedEx | Ground & Home Delivery | 139 | 5,000 | All packages |
| FedEx | Express (domestic) | 139 | 5,000 | All packages |
| UPS | Ground | 139 | 5,000 | All packages |
| UPS | Air services | 139 | 5,000 | All packages |
| USPS | Priority Mail | 166 | 6,000 | Packages > 1 cubic foot |
| USPS | Priority Mail Express | 166 | 6,000 | Packages > 1 cubic foot |
| DHL | Express (international) | 139 | 5,000 | All packages |
| Amazon | Shipping | 139 | 5,000 | All packages |
Moving freight via LTL (less-than-truckload)? Use our Freight Class Calculator to determine your NMFC freight class based on density — the same principle as DIM, but for pallet shipments.
Open Freight Class Calculator →Common questions about dimensional weight and parcel billing
Dimensional weight (DIM weight) is a pricing technique used by parcel carriers to account for the space a package occupies relative to its actual weight. It is calculated as: DIM Weight = (Length × Width × Height) ÷ Divisor. If the DIM weight exceeds the actual weight, carriers bill on DIM weight. This prevents shippers from sending large, light packages at the same price as small, heavy ones.
As of 2026, FedEx uses a divisor of 139 for domestic US shipments (Ground and Express). This means a package measuring 12 × 12 × 12 inches has a DIM weight of (12 × 12 × 12) ÷ 139 = 12.5 lbs. If the actual weight is less than 12.5 lbs, FedEx bills at 12.5 lbs.
USPS uses a divisor of 166 for Priority Mail and Priority Mail Express. This is a more favorable divisor than FedEx or UPS (larger divisor = lower DIM weight), making USPS competitive for lightweight, bulky packages like clothing, pillows, and lightweight consumer goods.
DIM weight applies when the calculated dimensional weight exceeds the actual weight of the package. Most major carriers apply DIM weight to all packages — not just large ones. A 10-lb box that is 20 × 20 × 10 inches has a DIM weight of (20 × 20 × 10) ÷ 139 = 28.8 lbs, so you'd be billed at 29 lbs.
To reduce DIM weight charges: (1) Use smaller boxes — every inch of unused space adds to your DIM weight. (2) Use packaging that closely conforms to product shape. (3) Compare carriers — USPS has a more favorable divisor for light packages. (4) Negotiate a custom divisor if you ship high volumes — some carriers offer divisors above 139 for contract customers. (5) Use poly mailers instead of boxes for soft goods.
Our partner network includes U.S. Customs Bonded warehouses, climate-controlled facilities, and full-service 3PLs across the Southeast.