How to Calculate Dimensional Weight for Shipping

If you have ever tried to use a shipping weight calculator, you have probably noticed that the estimate often doesn’t represent the actual weight of the package. That’s because carriers usually apply dimensional weight (also called DIM or volumetric weight), which is not a precise measure but a pricing technique. And to calculate shipping costs properly you will need a dimensional weight calculator.

Dimensional weight or volumetric weight is a pricing method used by carriers to avoid shipping lightweight and low-density shipments that take up too much space in their vehicles.

Carriers calculate dimensional weight as an abstract variable based on the length, width, and height of the package, which makes their business more cost-effective. Carriers began using this pricing method when charging clients for actual weight became unprofitable. Lightweight yet low-density shipments took up considerable space but brought no profits because of their cheapness.

To unify the pricing principles, carriers introduced dimensional weight; however, each company reserved the right to use its own density minimum, (one of the variables of the DIM weight), to calculate shipping prices.

To calculate the dimensional weight of your package, measure its length, width, and height. The dimensional weight formula:

(length × width × height) / DIM factor

The DIM factor (or shipping factor) is specific for each carrier. It represents the value of minimal density, chosen by the shipping company as a DIM divisor in the formula. This value is estimated in cubic inches per pound or cubic centimeters per kilogram for the imperial and metric systems, respectively.

The major carriers use dimensional weight universally, smaller companies use cubic size as the primary pricing factor.

Remember that when the actual weight exceeds the volumetric weight, the carrier applies the greater value for the shipping price. Compare the dimensional weight that you got from the formula with the package’s actual weight to determine the value that will be used by the carrier.

To obtain DIM weight in kg, multiply your final result in cubic inches by 0.0163 to obtain the measurement in kilograms.
To calculate dimensional weight in kg from pounds, multiple your final result by 0.45

FedEx has implemented the dimensional weight pricing technique across all its services. Unlike many other carriers, FedEx has one shipping factor. To calculate the DIM weight for a FedEx parcel, put 139 cu in/lb (or 5000 cm3/kg for the metric system) into the aforementioned dimensional weight formula. Use our FedEx Dimensional Weight Calculator.

USPS has been using volumetric weight since 2007. They call it shape-based postal pricing.

For the Global Express Guaranteed shipping option, USPS applies the International Air Transport Association (IATA) standard DIM factor of 166 cu in/lb (or 6000 cm3/kg for the metric system).

When shipping domestically through Priority Mail to Zones 5-9, put 194 cu in/lb (7000 cm3/kg) into the dimensional weight formula. USPS uses DIM weight only for parcels over 1 cubic foot/1,728 cu in.

The carrier uses two DIM factors to calculate the volumetric weight but applies this approach only to particular services.

UPS uses 139 cu in/lb (5000 cm3/kg) for:

• All international shipments
• Daily rates for parcels exceeding one cubic foot and shipping domestically
• All Canadian domestic packages except for the UPS Standard option

The 166 cu in/lb (6000 cm3/kg) shipping factor is used for:

• Daily rates for parcels less than or equal to one cu ft. shipping domestically
• Retail rates for parcels shipping locally
• Canada domestic parcels using the UPS Standard option

Instead of determining the volumetric weight of every shipment manually, you can try our UPS Dimensional Weight Calculator.

DHL volumetric weight across all its services is 139 cu in/lb (5000 cm3/kg). For packages shipping to the United Arab Emirates, however, the shipping factor is lower — 111 cu in/lb (4000 cm3/kg).

Canada Post expedited or regular shipment:

• the DIM formula is 6,000 cm3/kg (166 cu in/lb).

Canada Post Priority, Xpresspost, U.S., and International shipments:

• the Dimensional weight formula is calculated like this 5,000 cm3/kg (138 cu in/lb).

Purolator Air Services:

• Purolator uses the following shipping formula to calculate dimensional weight L x W x H /1728x15 cu in/lb or for calculation in kg L x W x H /28316 x 15.

Purolator Ground Services:

• Use this formula to calculate dimensional weight L x W x H /1728 x 10 (cu in/lb) or /28316 x 10 for cm3/kg.

If you want to accurately estimate the shipping rates for the products you sell, it is essential to know the volumetric weight of every item. Otherwise, you run the risk of presenting incorrect shipping costs to your customers. Calcurates can help you out with this. And these are the configuration steps:

1. Pick one of the 3 Volumetric Weight calculation methods available in Calcurates:
   1. Dimensions Method. Height * Width * Length = Volume. Volumetric Weight = Volume/Shipping Factor
   2. Volume Method. Volumetric Weight = Volume / Shipping Factor.
   3. Volumetric Weight Method. Volumetric Weight = Volumetric Weight.
2. Add product's dimensions, volume or pre-calculated volumetric weight (depending on the selected algorithm) in your e-commerce platform admin:
   • Shopify: use decimal or integer metafields
   • Magento: use decimal or integer product attributes
   • WooCommerce: use decimal or integer product parameters
3. Complete Volumetric Weight mapping settings for chosen calculation method
4. Select Volumetric Weight calculation method for your Shipping Options and specify the Shipping Factor
5. Enable Volumetric Weight for your Carrier Shipping Option

Now for this Shipping Option Calcurates will calculate the Volumetric Weight of the Shopping Cart, compare it with the Cart's regular weight and use the highest value for getting real-time shipping rates or calculating your own Table Rates. If you ship large items that would help you significantly increase the shipping rates accuracy.