Why density matters in LTL shipping.

warehouse freight density matters

In physics, density is described as a measurement of how tightly matter is packed together. It explains why some objects float on water and some sink, like a plastic toy floating in a bathtub. While density sits within the foundation of physics, it also takes on a crucial role in LTL freight shipping.

Let's take a closer look at some of the reasons why shippers need to consider and understand freight density's role in the shipping process.


How freight density impacts shippers.

The National Motor Freight Traffic Association (NMFTA) has established a set of standards, known as the freight classification system, which is designed to provide shippers with standardized prices for freight shipments when working with various carriers.

There are 18 freight classes, ranging from 50 to 500. As a general rule, the higher the freight class, the more it will cost to ship.


Here's a quick look at the estimated freight classes of commonly shipped items:

Commonly Shipped Item Class Based On Weight Range Per Cubic Foot Of
Garment Hangers 400 Less than 1 lb.
Steel or Wood Pallets 175 4 but less than 6 lbs.
Envelopes 70 Not applicable to this product
Restaurant Cooking Equipment 250 2 but less than 4 lbs.
Automotive Transmission 85 Not applicable to this product
Crated Machinery 92.5 10 but less than 12 lbs.
Ceramic Tile 60 Not applicable to this product


Classes are determined by a variety of factors:

  • Density
  • Freight's ability to be stored
  • Ease of handling
  • Liability

It could be stated that density is the most important element when determining the class of a shipment, as it sets the range for classification. To determine the density of a shipment, divide the total weight by the total cubic feet, or use a density calculator.

When calculating density, it's important to use a reliable scale and accurate measurements that include the packaging (measure from the most extreme points of the packaged shipment). The density before you package your freight is not likely equal to the total density of a shipment ready for pick up.

Once you've calculated an accurate density and assigned a freight class, you'll put the information on a bill of lading (BOL). With an accurate freight density calculation, you'll submit the BOL with confidence and avoid the costly consequences that can result from inaccuracies.


Why freight density matters to carriers.

Freight density isn't only an important factor to consider for shippers. For regional carriers, the primary factors that determine freight cost are P&D and dock, since the distance traveled is typically short. While freight density is important to regional carriers, it is not viewed as critical.

However, nationwide LTL carriers view freight density in a different light. With much longer routes, LTL carriers are always looking to maximize cube utilization and need to have accurate densities to do so. For these carriers, wasted space on the truck is equal to leaving dollars on the table.


Freight density: Where its role in LTL could be headed.

A little less than a year ago, our very own Tim Quinn wrote about the United Parcel Service and FedEx's plans to begin using density to determine small package and parcel pricing. He talked about the potential of this trend working its way into the LTL shipping industry.

However, for density-based pricing to take hold, it will require both shippers and carriers to buy in. For example, a large shipping customer paying their own freight adopting the new pricing structure could end up pushing more carriers and freight services out of the middle ground and into the corner of supporting the change. It will certainly be interesting to see where the LTL industry goes from here.


Final thoughts.

Density carries weight figuratively and literally in the LTL shipping industry. Only time will tell if its role expands in the near future with the changes that seem to be picking up momentum.

LTL shipping guide

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