How to Calculate Freight Density for Shipping

01/11/2019 — Leah Palnik

Density is a major factor in determining your freight class and your total shipment cost. In fact, many LTL carriers are relying more and more on freight density over actual weight to determine your rate. That's why it's important that you understand what freight density is and how to calculate it.

Freight density defined
Freight density measures how heavy a shipment is relative to the size of the shipment. The higher the density, the lower the classification and vice versa. A shipment with a high freight density weighs a lot relative to its size, such as densely packed books. A package with a low freight density weighs little relative to its size, such as a box filled with Styrofoam.

How to calculate freight density
Step 1. Measure the height, width, and depth of the shipment in inches. Measure to the farthest points, including skids or other packaging. On shipments with multiple pieces, repeat Step 1 for each piece.

Step 2. Multiply the three measurements (height x width x depth). The result is the total cubic inches of the shipment. If you have multiple pieces, multiply the height x width x depth for each piece. Take the results for each piece and add them together to get the total cubic inches

Step 3. Divide the total cubic inches by 1,728 (the number of cubic inches in a cubic foot). The result is the cubic feet of the shipment.

Step 4. Divide the weight (in pounds) of the shipment by the total cubic feet. The result is the pounds per cubic foot, i.e., density.

• For multiple pieces, add the weight of each piece together before dividing by the total cubic feet of the shipment.
• Round fractions to the nearest full cubic foot number.

Calculating freight density will also provide you with a recommended class for your shipment. The freight class chart below is an abbreviated scale you can use to help estimate the freight classification for your shipments.

Helpful tools
There are many factors that determine your freight class, aside from density, so these are estimates only. If you're looking for help to find your freight class, our team is standing by. For a quick and easy way to figure out your shipment density, check out our freight density calculator.