Package Dimensions Calculator
Calculate dimensional weight for your packages and determine shipping costs based on USPS, UPS, and FedEx standards. Optimize your packaging to reduce shipping expenses.
Calculate Your Package Dimensions Calculator
Understanding Dimensional Weight
Dimensional weight (also called volumetric weight) is a pricing technique used by shipping carriers to account for package density. It ensures that large but lightweight packages are charged appropriately, as they take up valuable cargo space despite weighing very little.
Carriers will charge you for shipping based on either the actual weight or the dimensional weight of your package, whichever is greater. This is known as the "billable weight."
How to Calculate Dimensional Weight
The formula for calculating dimensional weight is:
Dimensional Weight = (Length × Width × Height) ÷ Dimensional FactorThe dimensional factor (sometimes called a divisor) varies by carrier:
- USPS uses a divisor of 139 for all shipments
- UPS and FedEx use 166 for domestic shipments
- UPS and FedEx use 139 for international shipments
For example, a package measuring 15" × 12" × 10" with an actual weight of 2 pounds would have a dimensional weight of:
(15 × 12 × 10) ÷ 139 = 1800 ÷ 139 = 12.95 pounds with USPS
(15 × 12 × 10) ÷ 166 = 1800 ÷ 166 = 10.84 pounds with UPS/FedEx domestic
Package Size Categories
Carriers use different size categories to classify packages, which can affect shipping costs and handling requirements.
USPS Package Categories
USPS uses the Length + Girth formula for size categorization. Girth is calculated as 2 × (Width + Height).
| Category | Size Criteria | Max Weight |
|---|---|---|
| Regular Package | Length + Girth ≤ 84 inches | 70 lbs |
| Medium Package | Length + Girth ≤ 108 inches | 70 lbs |
| Large Package | Length + Girth ≤ 130 inches | 70 lbs |
| Oversized Package | Length + Girth > 130 inches | 70 lbs |
UPS and FedEx Package Categories
UPS and FedEx use both dimensional limits and Length + Girth calculations for their size categories.
| Category | Size Criteria | Max Weight |
|---|---|---|
| Standard Package | L ≤ 48", W ≤ 30", H ≤ 30" | 150 lbs |
| Large Package | Length + Girth ≤ 130 inches | 150 lbs |
| Oversized Package | Length + Girth ≤ 165 inches | 150 lbs |
| Special Handling | Length + Girth > 165 inches | May vary |
Freight Class and Density
For larger shipments, the National Motor Freight Classification (NMFC) system uses density (pounds per cubic foot) to determine freight class, which affects shipping rates.
| Freight Class | Density (lb/ft³) | Typical Items |
|---|---|---|
| 50 | ≥ 50 | Brick, cement, hardwood flooring |
| 55-65 | 30-50 | Books, canned goods, bottled beverages |
| 70-92.5 | 12-30 | Auto parts, hardware, machinery |
| 100-125 | 6-12 | Furniture, appliances, boxed items |
| 150-250 | 2-6 | Mattresses, clothing, plastic items |
| 300-400 | 1-2 | Light furniture, insulation materials |
| 500 | < 1 | Ping pong balls, light packaging |
Note: Lower freight classes (50-65) are less expensive to ship than higher freight classes (150-500).
Tips for Reducing Shipping Costs
For Dimensional Weight:
- Use appropriately sized packaging; avoid excess empty space
- Consider custom-sized boxes for your products instead of standard sizes
- Compress or vacuum-seal soft items when possible
- Consolidate multiple items into fewer shipments when feasible
- Compare different carriers, as dimensional factors vary
For Freight Class:
- Densify your shipment when possible (stack efficiently, minimize air space)
- Use proper packaging to prevent damage while maintaining density
- Consider palletizing multiple items to achieve better density
- Accurately declare freight class to avoid reclassification fees
Frequently Asked Questions
If your carrier is charging for a weight higher than your package's actual weight, they're likely using dimensional weight pricing. When a package has a large volume but relatively low weight, carriers calculate a dimensional weight based on the package's dimensions. They then charge you for either the actual weight or the dimensional weight, whichever is greater. This practice ensures that lightweight but bulky packages that take up significant cargo space are priced appropriately. To reduce these charges, consider using smaller packaging with less empty space.
Different carriers use different dimensional divisors (or dimensional factors) to calculate dimensional weight:
- USPS uses a divisor of 139 for all shipments
- UPS and FedEx use 166 for domestic shipments
- UPS and FedEx use 139 for international shipments
A higher divisor results in a lower dimensional weight, which is more favorable for customers. That's why UPS and FedEx domestic shipments (with a divisor of 166) generally yield a lower dimensional weight than international shipments or USPS shipments (both with a divisor of 139). These divisors can change over time as carriers update their pricing policies.
Girth is the measurement around the thickest part of a package, perpendicular to its length.
To calculate girth:
- Identify the longest side of your package, which is considered the length
- The remaining two dimensions (width and height) are used to calculate girth
- Formula: Girth = 2 × (Width + Height)
For example, if your package measures 20" × 12" × 8":
- Length = 20"
- Girth = 2 × (12" + 8") = 2 × 20" = 40"
- Length + Girth = 20" + 40" = 60"
Carriers use the Length + Girth measurement to determine package size categories and any applicable surcharges.
Freight class is a standardized classification system used for less-than-truckload (LTL) shipping that categorizes goods based primarily on their density. The National Motor Freight Classification (NMFC) system assigns items to classes ranging from 50 to 500.
Lower class numbers (50-85) represent denser, more durable items that are easier to transport, resulting in lower shipping rates. Higher class numbers (125-500) represent less dense, more fragile, or more difficult-to-handle items, resulting in higher shipping rates.
Freight class affects shipping costs in several ways:
- Higher classes pay higher rates per hundred pounds
- Incorrect class declaration can result in reclassification fees
- Some classes may require special handling or equipment
To minimize costs, pack your shipments densely and accurately declare the appropriate freight class based on the density calculation.
To reduce dimensional weight charges:
- Right-size your packaging: Use the smallest possible box that safely fits your items
- Eliminate empty space: Use appropriate void fill or consider custom packaging
- Compress items when possible: Use vacuum bags for soft goods like clothing or bedding
- Fold or disassemble items: When safe to do so, reduce the overall dimensions
- Split overly large packages: Sometimes shipping two smaller packages costs less than one large one
- Compare carriers: Different carriers have different dimensional factors and pricing policies
- Negotiate terms: High-volume shippers may be able to negotiate better dimensional factors
Remember that reducing package dimensions has a multiplying effect on dimensional weight, since it's calculated using all three dimensions (length × width × height).
UPS/FedEx and USPS use different criteria for categorizing packages:
UPS/FedEx Categories:
- Focus on both specific dimension limits and Length + Girth
- Standard packages must be ≤ 48" in length and ≤ 30" in width and height
- Have higher weight limits (typically up to 150 lbs)
- Apply large package surcharges at 130" Length + Girth
- Consider packages over 165" Length + Girth as special handling
USPS Categories:
- Primarily use Length + Girth for categorization
- Have lower weight limits (maximum 70 lbs for most services)
- Categorize packages exceeding 130" Length + Girth as oversized
- May offer more favorable rates for smaller, lighter packages
These differences mean that the same package might fall into different categories depending on the carrier, which can significantly affect shipping costs. It's often worthwhile to compare rates across carriers for your specific package dimensions and weight.
Yes, there are several exceptions to dimensional weight pricing:
- Service-specific exemptions: Some services, like USPS Priority Mail Flat Rate or Regional Rate, charge by package type rather than weight or dimensions
- Negotiated contracts: High-volume shippers may negotiate custom dimensional factors or exemptions
- Minimum charges: Very small packages might not benefit from dimensional weight calculations if the carrier has a minimum charge
- Special items: Some items, like tubes, irregular shapes, or extremely long items, may have special pricing rules
- Certain destinations: Some carriers may apply dimensional weight differently for certain international destinations
Additionally, USPS does not apply dimensional weight to packages under 1 cubic foot (1,728 cubic inches) when using certain services. Always check with your specific carrier for their current policies and exceptions, as these rules can change over time.
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