Dimensional Weight Calculator | USPS, DHL, UPS, FedEx

What is Dimensional Weight?
Dimensional (DIM) weight pricing is a formula used by shipping carriers to determine the cost of shipping a package based on its volume. This method ensures that carriers consider both the weight and size of packages when setting shipping rates. Dimensional weight pricing allows carriers to incorporate the size of packages into their pricing structure. After all, the number of packages that can fit in one truck or container depends not only on weight but also on the size of the boxes.

Dimensional Weight vs. Volumetric Weight
Dimensional weight and volumetric weight are used interchangeably in shipping. Both refer to the calculation method based on a package’s volume, rather than its actual weight. This ensures that large but light packages are priced fairly, as they occupy significant space in transport vehicles. The calculation involves multiplying the package’s length, width, and height, then dividing by a factor determined by the shipping company.

Why Dimensional Weight Pricing?
Dimensional weight pricing helps carriers like FedEx, UPS, and USPS account for the space a package occupies during transportation, a critical factor in an era of growing eCommerce shipping. The space available in trucks and aircraft is limited, so shipping companies must charge based on both size and weight.

Packages that are light yet large will likely incur higher shipping costs due to DIM weight pricing. However, if your package is heavy and small, you’ll typically only pay based on its actual weight.

What is a DIM Factor?
Each shipping carrier uses a specific number called the DIM factor to calculate a package’s dimensional weight. The DIM weight is calculated by dividing the package’s volume by the carrier’s DIM factor.

FedEx, UPS, and USPS each update their DIM factors regularly. For example, in 2019, USPS changed its DIM weight pricing model to apply to packages greater than 1,728 cubic inches. DIM weight pricing does not apply to USPS flat-rate shipments.

How to Calculate Dimensional Weight
To calculate dimensional weight, multiply the package’s length, width, and height, then divide by the DIM factor used by the carrier. The shipping cost is based on whichever is greater between the dimensional weight and the actual weight of the package.

For example, if a package has a DIM weight of 8 pounds and an actual weight of 5 pounds, it will ship based on the 8-pound DIM weight. Conversely, if the actual weight is 10 pounds, the shipping charge will be based on the 10-pound actual weight.

FedEx Dimensional Weight in 2025
FedEx uses a DIM factor of 139, which has been in effect since 2017. For example, a 10” x 10” x 10” package with this factor will have a DIM weight of 8 pounds. FedEx has also updated its billing rates, making them comparable to UPS’s. UPS may have a slight price advantage in certain zones, while FedEx may be cheaper in others.

UPS Dimensional Weight in 2025
UPS’s DIM factor remains 166 for retail shippers and 139 for daily rate shippers. A 10” x 10” x 10” package will have a DIM weight of 7 pounds with retail rates but 8 pounds with daily rates. This variation shows the cost difference between shipping methods.

USPS Dimensional Weight in 2025
USPS lowered its DIM factor from 194 to 166 in 2019, aligning with UPS’s retail rates. While USPS’s volumetric weight penalty is smaller than FedEx and UPS, the rates still apply to zones 5 and up, meaning shorter-distance shipments might not be affected by DIM weight.

How FulfillMe Helps Clients Reduce Dimensional Weight Charges
Dimensional weight pricing doesn’t have to hurt your business. When you partner with a 3PL like FulfillMe, you benefit from volume discounts, which can help reduce shipping costs. FulfillMe ships large quantities of packages with major carriers and negotiates favorable DIM factors, passing savings onto you.

By working with FulfillMe, you can enjoy both lower rates per pound and better DIM factor terms, helping you save money on large or bulky items while ensuring faster, more efficient shipping.