What Is Dimensional Weight and How Is It Calculated?

What Is Dimensional Weight and How Is It Calculated?

What is dimensional weight? How is it calculated? This can factor into the price of your freight shipping, so knowing a few things about it can help you plan your business expenses better in the future.

What Is Dimensional Weight?

Dimensional weight is also known as volumetric weight or DIM weight. It's a pricing method utilized by postal services and commercial freight companies. Carriers that only focus on the weight dimension might run the risk of carrying lighter packages that take up a lot of room, and that can result in losses to them. So, they focus on a combination of the weight and dimensions of a package based on the density of a package rather than just size or weight alone.

How DIM Weight Is Different from the Actual Weight?

The weight of a box can always be measured in just pounds or kilograms, but using a dimensional weight calculation means that anyone dealing with freight commodities can know how much cubic size a package will take in their warehouses, trucks, and planes.

Weight alone might be all they need to know for a package that's in a standard box, but for custom-packed units, the dimensions are necessary to determine how much space a package will take. Otherwise, trucks might get either overloaded or underloaded. Both are bad situations for any business trusted with moving parcels around the country.

What Is the DIM Factor?

weight of a box

The DIM factor is also known in DIMS shipping as the dimensional factor. It's a divisor that many freight carriers use in their calculations. It's a representation of the total package volume permitted per weight unit. Keep in mind that not all carriers use their own DIM factors, as their service levels and company needs dictate things a lot. At the time of writing, USPS priority mail had a DIM factor listed at 166. However, FedEx and UPS were both at 139.

How Is Dimensional Weight Calculated?

You can account for the dimensional factor when you know how to calculate box weight and measure all three sides. Then, you'll have some idea if you'll get hit with DIM weight or actual weight.

Determine the cubic size of your package by measuring the three sides and then multiplying the three numbers together. That's your cubic size in inches. To get the DIM weight, you divide that cubic size by 139 for UPS and FedEx. If you get a decimal, round up to the nearest integer.

Why DIM Weight Is Used by Parcel and LTL Carriers?

Many carriers have started using both DIM weight and shipping weight in their cost calculations. UPS and FedEx have been doing it going back to 2015. They find it useful for two different kinds of items. One is heavy products in small packages. The other is light items in large packages. They do this so they don't lose money on light and bulky items.

Shipping volumes are hitting historic highs around the world, so now even smaller carriers are looking to make the most of the space they have in planes, trucks, and shipping containers so they can be competitive. This means many are creating DIM weights that just weren't there this time last year. It's having a profound impact on shipping costs.

What Is the DIM Pricing and How to Optimize It?

dimensional weight

DIM pricing involves the height, width, and length of a package in determining its billable weight. However, it's not always used. For most 3PL company carriers, it doesn't take effect unless the actual package weight is less than the DIM weight.

For example, a pair of dumbbells could fit in a rather small box. Their dimensional weight would be much lower than their actual weight, but the carrier would have to have people lift a heavy box and it could also strain their vehicles and package conveyors. Actual weight is billed for this, but DIM weight might be used for artwork that is light but eats up the room.

To optimize, you need to know that the greater of the two is what you will be charged. Also, pack your shipments with as little room as possible.


Knowing the dimensional weight formula that your carriers use helps you plan your shipping and freight expenses accordingly. In a time of high inflation and supply chain disruptions, it's crucial to minimize your expenses so you can stay competitive and avoid handing down costs to your customers who are shopping for the best deals they can find. It's also more of your profit you can keep. If you're not sure what a 3PL company charges for this, then contact us at Cowtown Express to get a quote for your next shipment.

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