Dimensional weight (also known as DIM weight) might be the reason if you are getting a higher shipping cost than you expected for sending items internationally. International carriers like DHL, FedEx, UPS, and USPS don't consider package weight alone, they also take a look at how much space a package takes up in transit. This is particularly for light and bulky items. The charge is based on the higher of the actual weight or dimensional weight, which is also referred to as the billable weight, for each shipment.
Continue reading to find out what dimensional weight is, why it is important when shipping internationally, how to calculate it, what the dimensional factor is, and how you can reduce shipping expenses. By knowing these details, you can pack more wisely, save from any hidden extra fees and save money on every shipment you make internationally.
The dimensional weight pricing, also known as DIM weight or volumetric weight pricing, is one of the pricing methods that international carriers use to determine the cost of shipping a package based on the volume rather than the actual weight. For each shipment, there are two weights:
The carrier does the comparison and charges you whichever is higher. This pricing follows the concept of paying for the cargo space that is used during the transportation process, especially for large and heavy packages. A box containing pillows, for instance, can weigh just 4 lbs, but occupy the same aircraft space as a much heavier package. In this way, it will be charged based on the dimensional weight of the shipment and not the actual weight.
The importance of dimensional weight is that there is limited space in delivery vehicles, airplanes and trucks. If packages are light, but they are large, then they will occupy a huge amount of space in a carrier's truck, which causes them to lose out on a lot of freight.
For this reason, big companies like DHL, FedEx, UPS, and USPS have adopted dimensional weight pricing to charge for shipping more accurately. DIM weight is important when shipping internationally for the following reasons:
For packages that are light, but large, dimensional weight may be a larger factor than actual weight in determining the shipping price.
Once you have the dimensions of your package, calculating dimensional weight is easy. When preparing to ship internationally, take accurate measurements of your parcel as there is a risk of it being charged as a higher billable weight in the case of a marginally oversized box.
Most carriers use a dimensional factor (DIM divisor) to determine dimensional weight, which is based on the length, width, height of the package.
First, determine the dimensions of your package. Use the same unit of measurement for each side, for example, inches or centimeters. Measuring the accuracy is important because the carriers use these measurements to decide how much space your package will take up during the shipping process.
After having the dimensions, multiply length × width × height to determine the package's total volume. This will provide the cubic capacity of your shipment which is what carriers use to determine how much cargo space your shipment requires.
Formula:
Package Volume = Length × Width × Height
To determine the dimensional weight, then divide the package volume by the carrier's dimensional factor (DIM divisor). The DIM factor can differ from one carrier to another and from one service to another, so the end outcome could differ based on what carrier or service you make use of.
Formula:
Dimensional Weight = Length x Width x Height / DIM Factor
After calculating the dimensional weight, compare it with the package's actual weight. The heavier weight will be used by the carrier as the billable weight. If the dimensional weight is higher than actual weight, then you will pay according to the size of the packages and not by the actual weight.
The dimensional factor, also known as the DIM factor or dimensional divisor, is a number used by carriers to calculate dimensional weight based on the volume of a package. It is one of the components of the DIM weight formula and has an impact on your shipping prices. The DIM factor varies depending on the carriers' pricing policies and cargo space available for shipping services.
For instance, many international express services use 139 (inches) or 5,000 (centimeters) as a divisor, and other services might use a different figure. The smaller the DIM factor, the higher the dimensional weight, and the more it costs to ship. A higher DIM will result in a lower dimensional weight, which may lead to a lower dimensional weight for the same package. This is why the DIM factor is an important element of calculating the cost for international shipping.
Dimensional weight is a factor in shipping costs because carriers charge the maximum of the actual weight or dimensional weight. If a package is light in weight but large in size, you will be charged for the space it takes, rather than the weight. Dimensional weight can raise the cost of shipping for international shipping in a few different ways:
A package measures 30 × 30 × 36 cm and weighs 50 kg.
Dimensional Weight = (30 × 30 × 36) / 5,000 = 6.48 kg
Actual Weight = 50 kg
The actual weight will be more, so you will be charged 50 Kg.
A package measures 112 × 22 × 89 cm but weighs only 2 kg.
Dimensional Weight = (112 × 22 × 89) / 5,000 = 43.9 kg
Actual Weight = 2 kg
In this instance, the carrier will be charged for 43.9kg, as the package will take up a lot of cargo space compared to its weight.
The most cost effective strategies for dimensional weight savings are to adopt the smallest packaging possible, eliminate any empty space, ship multiple orders together and repack bulky retail boxes.
These easy measures reduce the volume of your package and may also lower the billable weight, potentially also lowering costs when you ship internationally.
Select a box that closely matches your product. Oversized boxes make packages bigger and can result in increased dimensional weight charges. A properly sized box will help you save from unused space and you will keep your items intact.
If there are large spaces inside the package, additional material fillers will be needed that will make the package size larger. Only package the items with the needed cushioning to protect them during transit. Shorter empty spaces help to reduce package volume and possibly reduce shipping costs.
Many online retailers ship products in boxes, which are far too large. These products can be repacked into a smaller box for shipment, eliminating excess bulk and reducing dimensional weight without sacrificing protection.
If you have multiple orders from multiple stores, you may be able to save on shipping volume by consolidating multiple packages. Package consolidation also reduces the amount of duplicate packaging materials used and reduces total shipping costs.
Use materials like bubble wrap, air pillows or packing paper instead of bulky fillers to protect your items. These materials will keep your products safe and consume less internal space in the box.
Large items like furniture, sports equipment or other products may be disassembled prior to shipping. Filling them in a smaller box will decrease the size of the package and will lower the dimensional weight.
Each carrier has its own pricing and dimensional factors. Before you book a shipment, you can take the time to compare shipping services to determine which is the cheapest option for the size of the package and its destination.
Dimensional weight is one of the biggest factors affecting international shipping costs, especially for large but lightweight packages. Understanding how carriers determine DIM weight can help you get a more accurate estimate of shipping costs and prevent any surprises.
International shipping costs can be reduced by reducing billable weight, empty space and repacking oversized boxes, and consolidating shipments with proper packaging. At Ship7, we also make international shipping more affordable by helping customers save on shipping costs with smart package consolidation and repacking services.


