When your package is large but not that heavy, it could get charged based on the dimensional weight (or DIM weight) instead of its actual weight 🙈
Pirate Ship automatically calculates your package's DIM weight
Pirate Ship automatically calculates the DIM weight of every package. You may be charged DIM weight pricing if you're shipping large & lightweight items like pillows, wreaths, or a handbag.
When DIM Weight Applies: DIM weight can apply to any domestic package larger than 1 cubic foot (for example, if the dimensions are 12x12x12" or larger).
DIM Weight for USPS Shipments: For USPS, DIM weight surcharges apply only to weight-based Priority Mail, Priority Mail Express, and USPS Ground Advantage.
DIM Weight for UPS Shipments: For UPS, DIM weight applies to all services regardless of size, so you can be charged DIM Weight on UPS shipments under a cubic foot.
There is an exception for Ground and 3-Day Select, as UPS waives DIM Weight if shipments using those services are under a cubic foot 👍
Calculating DIM weight
Pirate Ship automatically calculates the DIM weight of each shipment, and these charges only apply if your package's DIM weight exceeds its actual weight.
The DIM Weight Equation: To determine if DIM weight pricing will apply to your shipment, you can multiply the Length * Width * Height of your shipment, and divide that total by 166 ✏️
Laid out, the DIM Weight formula is: Length x Width x Height / 166
If the number you get is higher than the actual weight of your shipment, USPS and UPS will use that number as the "dimensional weight" of your package when determining the cost of your label.
An example of when DIM weight applies
Imagine you've got a box measuring 26x26x5" that weighs 3 lbs, being sent from New York to Los Angeles. Due to DIM weight pricing, the Priority Mail rate for this shipment would cost $72.17 😮
By multiplying the dimensions (26 * 26 * 5), the total we get is 3,380
When dividing 3,380 by 166, we get a total of 20.4
Because 20.4 is higher than the original weight of 3 lbs, USPS will calculate the rate of this shipment as if it weighed 21 lbs*
*Note: Both USPS and UPS round up to the nearest whole pound when calculating DIM weight. So, 20.4 pounds gets rounded up to 21 lbs.
If your dimensions aren't whole numbers, you'll also want to round your dimensions down or up to the nearest whole inch in the DIM weight formula. Here's that laid out once again:
Length x Width x Height / 166
Use a different divisor for international UPS shipments
Domestic DIM Weight Divisor: USPS and UPS use 166 as their DIM weight divisor for domestic shipments.
International DIM Weight Divisor: For international UPS shipments, divide by 139.
How can I avoid DIM weight pricing?
USPS no longer offers a way to avoid those dimensional weight surcharges, even if you choose to ship directly from the Post Office 😥 However, there are still ways to help reduce your cost to ship!
Here are some strategies to avoid DIM weight pricing:
Optimize Packaging Size: Use the smallest packaging possible for the item you're sending
Cutting Boxes: See if you can cut your box down to a smaller size
Use Multiple Boxes: If possible, separate the items being sent into multiple, smaller shipments
Use the "Box in a Bag" Method: If the box can fit inside of an envelope or poly mailer with room to spare, see if you can find a lower rate through the "box in a bag" trick
The "box in a bag" method is a strategy of putting your box inside a loose-fitting poly mailer to qualify for USPS Priority Mail Cubic rates
UPS handles DIM almost exactly the same as USPS
DIM for UPS shipments works almost identically to DIM for USPS. Here are the key things to know about DIM weight pricing for UPS shipments:
Domestic DIM Divisor: UPS uses the same DIM divisor for domestic shipments as USPS (166), which means that the math stays the same as it does for USPS shipments.
Domestic and International Shipments: Unlike USPS, UPS applies DIM charges to both domestic and international shipments.
For international shipments, UPS uses 139 as the DIM divisor (so, DIM charges on international packages are even more expensive).
Exceptions to DIM Weight Pricing: For the domestic services Ground and 3 Day Select, UPS waives dimensional weight for packages less than 1728 cubic inches (1 cubic foot).
For Ground and 3 Day Select services only, DIM weight applies only if your package's Length x Width x Height is 1728 cubic inches or more.
If this is the case, divide your box's cubic volume by 166 to determine the minimum billable weight. That new weight is what will be used to determine the cost of shipping.
All Other Domestic UPS Services: Outside of Ground and 3 Day Select, DIM weight pricing applies to all other domestic UPS services (like 2nd Day Air, Next Day Air, etc.) and all international UPS services, regardless of package size.
Dimensional weight will be taken into account even if your package is smaller than 1 cubic foot (1728 cubic inches), and applied if it leads to a "heavier" weight than the actual weight.
Even if your UPS package is tiny, its DIM weight may be heavier than its actual weight... and if it is, you'll pay DIM weight pricing 😅
Chat with our Support Crew if ye need help
Still sailin' in murky waters Cap'n? Our support team is happy to help - chat with us by clicking the blue icon or send us an email at support@pirateship.com 😃