Dimensional Weight Calculator
Calculate DIM weight (volumetric weight) to find your chargeable shipping weight for FedEx, UPS, and USPS
FedEx Ground, FedEx Express, UPS Ground, UPS Air
Package Dimensions
About This Tool
Dimensional weight (DIM weight) is a pricing technique that parcel carriers like FedEx, UPS, and USPS use to account for package volume, not just actual weight. Introduced widely in 2015, it prevents carriers from filling trucks with lightweight but bulky packages—essentially shipping "air."
How Billing Works
Carriers compare your package's actual weight (scale weight) against its dimensional weight (calculated from volume). Whichever is greater becomes the "chargeable weight" that determines your shipping cost.
DIM Weight vs LTL Density
If you ship LTL freight, you're familiar with density (lbs per cubic foot) which determines freight class. DIM weight is the inverse concept—it converts volume INTO a weight equivalent for billing.
Density = Weight ÷ Cubic Feet → For LTL class
DIM Weight = Cubic Inches ÷ Factor → For billing
When to Use This Calculator
- • Estimating parcel shipping costs
- • Comparing packaging options
- • Determining if LTL might be cheaper
- • Understanding unexpected shipping charges
The DIM Weight Formula
Formula (Imperial)
DIM Weight (lbs) = (L × W × H in inches) ÷ DIM Factor
Standard DIM Factors
| Carrier | Factor |
|---|---|
| FedEx / UPS (daily rates) | 139 |
| USPS / UPS (retail rates) | 166 |
| International Air (IATA) | 166 |
| Metric (cm³/kg) | 5000 |
Example Calculation
Package: 30" × 12" × 12", weighs 10 lbs
Volume: 30 × 12 × 12 = 4,320 in³
DIM Weight: 4,320 ÷ 139 = 31.1 lbs
Chargeable: 31 lbs (DIM > actual)
In this example, the carrier would bill based on 31 lbs rather than the 10 lb actual weight.
Tips to Reduce Dimensional Weight Charges
Use the smallest box possible
Avoid excess void fill by choosing a box that closely fits your product.
Consider poly mailers for soft goods
Clothing and textiles ship more efficiently in flexible packaging.
Consolidate multiple items
Shipping items together in one box is often cheaper than multiple packages.
Switch to LTL for large shipments
LTL freight uses density-based pricing, which is often more economical for bulky items.
Disassemble when possible
Furniture and equipment may ship cheaper when broken down into flat-pack boxes.
Negotiate your DIM factor
High-volume shippers can often negotiate better DIM factors with carriers.
Frequently Asked Questions
What is dimensional weight?
Dimensional weight (DIM weight or volumetric weight) is a pricing method that accounts for package size, not just actual weight. It's calculated by multiplying length × width × height and dividing by a DIM factor. Carriers charge based on whichever is greater: actual weight or dimensional weight.
What is the DIM factor for FedEx and UPS?
FedEx and UPS both use a DIM factor of 139 for domestic shipments (ground and air) for customers with daily pickup accounts. Retail rates (UPS Store drop-off) use 166. USPS also uses 166. International shipments typically use 166 (IATA standard).
What is chargeable weight?
Chargeable weight is the weight used to calculate your shipping cost. Carriers compare your package's actual weight against its dimensional weight and bill based on whichever is greater. If your package is light but bulky, you'll likely be charged by dimensional weight.
Why am I being charged more than my package weighs?
If your shipping cost seems high for a light package, you're likely being billed by dimensional weight. This happens when your package takes up significant space relative to its weight. Carriers adopted this pricing because truck and plane capacity is limited by volume, not just weight—they can't afford to fill vehicles with lightweight, bulky packages.
Does LTL freight use dimensional weight?
No, LTL freight carriers do not use dimensional weight. Instead, LTL pricing is based on freight class, which is determined by the shipment's density (weight ÷ cubic feet), along with other factors like handling requirements and stowability. For bulky, lightweight items, LTL freight is often more economical than parcel shipping.
What is the difference between DIM weight and density?
Density (lbs per cubic foot) is used by LTL carriers to determine freight class. Dimensional weight converts volume into a billing weight for parcel carriers. They're inverse concepts: density divides weight by volume, while DIM weight divides volume by a factor to get a weight equivalent.
How can I reduce dimensional weight charges?
Use the smallest box that safely fits your items, avoid excess void fill, consider poly mailers for soft goods, consolidate multiple items into one package, and disassemble products when possible. For large/bulky items, consider switching to LTL freight which uses density-based pricing. High-volume shippers can also negotiate better DIM factors with carriers.
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