Freight Density: How It Affects Freight Class & Cost

As the demand for freight shipping increases with the influx of e-commerce, and the driver shortage continues, freight pricing is moving from weight to freight density. This is because carriers that are charging shippers based purely on the weight of their product are losing space and money.

In this article, we will review exactly what freight density and dimensional weight pricing are, and how it will affect your freight costs.

What is Freight Density

Freight density is the space an item occupies in relation to its weight. This is determined by dividing the weight of the item in pounds by the volume in cubic feet—measurements that carriers may verify with a freight dimensioner at the dock. You find the total cubic feet by taking height x width x depth and diving that number by 1,728 (the number of cubic inches in a cubic foot).

For example, your 40" by 48" pallet has a height of 48" and a weighs 425lbs. (40 x 48 x 48)/ 1,728 gives you a volume of 53.33 cubic ft. You would then take your weight of 425/53.33 to give you a density of 7.97.

What is Dimensional Weight Pricing?

Dimensional weight pricing takes into account the space occupied by the package, along with its weight, rather than just its weight alone. It takes into account its freight density. Although, between the dimensional weight, and the actual weight, whichever is larger is the billable weight.

For example, if a customer purchases a pair of socks, and the warehouse packages them in a considerably larger box than needed, then the shipper will be charged much more for this package based on dimensional weight pricing. Because although the package is very light, it is taking up unnecessary amounts of space that could be used for other products on the truck.

How Does Density Affect Your Classification?

Freight classes are designed to help form common standard freight pricing for shipments, which is useful when using multiple carriers, warehouses, and brokers. Freight classes are defined by the National Motor Freight Traffic Association (NMFTA) and are based on:

Weight
Length and height
Density
Ease of handling
Value
Liability (theft, damage, breakability, and spoilage)

There are 18 freight classes, ranging from 50 to 500.

Your freight density is a major factor in determining your freight class. Essentially, the higher density your product is, the lower classification (typically 50-85), and the more fragile/less dense the product usually have higher classifications (usually 125-500).

How Does Density Affect Your Freight Cost?

Now that we've learned how density affects your classification, it's time to get into how all of this ultimately affects your cost to ship. As stated above, the end price is going to be based on whichever is greater, the dimensional weight or actual weight.

When the dimensional weight is larger than the actual weight, it may seem unfair to the shipper. It will look like you are paying for imaginary weight. The important thing to remember is to make your package as small as possible. You want to make your dimensional weight smaller than your actual weight.

To sum this up, the higher your density, the less space it takes on the truck—reducing your risk of cubic capacity charges—and the lower your classification, which decreases your rate for every hundred pounds you ship. In addition to cost savings, the denser your package the lower risk of potential damage.

Final Thoughts

Understanding freight density and dimensional weight pricing is essential for managing your shipping costs effectively. By optimizing your packaging to increase density and reduce dimensional weight, you can lower your freight classification and save money on every shipment. The key is to make your packages as compact as possible while still protecting your products.

A solid 3PL partner can help you define your class, and give advice on the best packaging for your product. In addition, they can help assist you with other ways to reduce your LTL freight costs overall. To learn how Redwood can increase your bottom-line by decreasing LTL freight costs, contact us.

FAQs

What is freight density in shipping?

Freight density is the amount of space an item occupies relative to its weight. Carriers calculate it by dividing the shipment’s weight in pounds by its volume in cubic feet. Volume is found by multiplying height × width × depth and dividing by 1,728, the number of cubic inches in a cubic foot. Higher density usually means a more favorable freight classification.

How does dimensional weight pricing work for freight shipments?

Dimensional weight pricing charges for the space a shipment takes up as well as its actual weight. The billable weight is whichever is larger: the dimensional weight or the actual weight. That means a light but oversized shipment can cost more than expected because it occupies valuable trailer space that could have been used more efficiently.

How does freight density affect freight class?

Freight density is a major factor in freight class assignment. In general, denser freight falls into lower classes, typically 50 to 85, while lighter, less dense, fragile, or hard-to-handle freight often lands in higher classes, usually 125 to 500. Freight class is based on multiple factors, including density, handling, value, and liability.

Why can low-density freight increase shipping costs?

Low-density freight can increase shipping costs because it takes up more trailer space without adding much weight. That can raise the billable weight under dimensional pricing and may also push the shipment into a higher freight class. In addition, bulky freight can create cubic capacity charges, which makes packaging efficiency an important cost control lever.

How can I lower freight costs by improving freight density?

You can lower freight costs by making shipments as compact as possible while still protecting the product. Smaller packaging reduces dimensional weight, helps keep freight density higher, and can lower the freight class assigned to the shipment. That combination can reduce the rate per hundred pounds and lessen the chance of cubic capacity charges.

What is the difference between actual weight and dimensional weight?

Actual weight is the real weight of the shipment on a scale, while dimensional weight is based on how much space the shipment occupies. For billing, carriers use whichever is greater. That means a large, lightweight package may be billed on dimensional weight instead of actual weight if it consumes more space than its weight justifies.

How do carriers calculate freight density at the dock?

Carriers may verify freight density with a freight dimensioner at the dock. The calculation uses the shipment’s measured dimensions to determine volume, then compares that volume to the shipment’s weight. If the measured dimensions or packaging are inaccurate, the freight class and billable weight can change, which affects the final shipping charge.