Freight density determines how much space your shipment takes up relative to its weight. Use our density calculator to get pounds per cubic foot in seconds. Just enter the weight and dimensions of your shipment, and the tool does the rest.
Knowing your freight density helps you estimate shipping costs, verify your freight class, and avoid unexpected carrier adjustments. The calculator works for palletized freight, boxes, crates, and cylindrical shipments.
This calculator provides estimates for planning purposes. Always confirm freight class and rates with your carrier before booking.
Get started with the freight density calculator
To get started, gather two values: the total weight of your shipment (in pounds) and its dimensions (length, width, and height in inches).
Enter those numbers into the calculator form on this page. The tool will:
- Multiply length × width × height to get total cubic inches.
- Divide by 1,728 to convert cubic inches to cubic feet.
- Divide the weight in pounds by the cubic feet to return density in pounds per cubic foot (PCF).
If you're shipping multiple pieces, measure each one separately. Then combine the total weight and total cubic feet before calculating density.
Freight density formula
The formula for density is straightforward. Density equals weight divided by volume.
For freight, that means:
Density (PCF) = Weight (lbs) ÷ Volume (cubic feet)
This gives you pounds per cubic foot, the standard unit carriers use to classify and price LTL shipments.
How to calculate density in pounds per cubic feet
Here's the step-by-step process:
- Weigh the shipment in pounds. Include packaging and the pallet if applicable.
- Measure the length, width, and height in inches.
- Multiply length × width × height to get total cubic inches.
- Divide total cubic inches by 1,728 to convert to cubic feet.
- Divide the weight by cubic feet.
Example: A shipment weighs 90 pounds. Its dimensions are 30 × 24 × 18 inches.
- 30 × 24 × 18 = 12,960 cubic inches
- 12,960 ÷ 1,728 = 7.5 cubic feet
- 90 ÷ 7.5 = 12 pounds per cubic foot
That density figure feeds directly into freight classification.
Convert cubic inches to cube in cubic feet
One cubic foot equals 1,728 cubic inches. To convert, divide the number of cubic inches by 1,728.
- 10,368 cubic inches ÷ 1,728 = 6 cubic feet
- 13,824 cubic inches ÷ 1,728 = 8 cubic feet
This conversion is the step most people skip or get wrong. The calculator handles it automatically, but understanding it helps you verify results on your own.
How to measure your shipment dimensions
Accurate dimensions are critical. Even a small measurement error can shift your freight class and change your rate. Always measure in inches at the widest, tallest, and longest points of the shipment.
Measure palletized freight (length, width, and height)
For palletized freight, measure the entire footprint, including the pallet and any overhang.
- Length: Measure the longest side of the pallet or the cargo, whichever extends further.
- Width: Measure the widest side the same way.
- Height: Add the height of the pallet (typically about 6 inches) to the height of the stacked cargo.
If your cargo weighs 90 pounds and the pallet weighs approximately 30 pounds, your total shipment weight is 120 pounds. Always include pallet weight.
Freight stacked unevenly or bulging past the pallet edge? Measure to the outermost point. Carriers bill on the space the shipment actually occupies, not the pallet dimensions alone.
Measure cylindrical shipments
Cylindrical shipments like drums and rolls need special attention. You cannot simply multiply diameter by height.
Instead, measure the density of a cylindrical shipment by treating the footprint as rectangular or elliptical, depending on carrier requirements. Most carriers use the bounding box method:
- Measure the diameter of the cylinder. This becomes both the length and width.
- Measure the height or length of the cylinder (whichever is the longest axis).
- Multiply diameter × diameter × height to get cubic inches.
- Divide by 1,728 to get cubic feet.
This approach reflects how the cylinder sits on a trailer. It occupies a square footprint equal to its diameter on each side.
Freight density and freight classification
Density is one of the most important factors in determining your freight class. Lower density generally means a higher class number and a higher shipping rate.
How density determines your freight rate
Carriers use density to assign a freight class between 50 and 500. Class 50 (the lowest) covers dense, easy-to-handle freight. Class 500 covers light, bulky items that take up a lot of trailer space relative to their weight.
Here's a simplified breakdown:
| Density (PCF) | Approximate Freight Class |
|---|---|
| 50+ | 50 |
| 35–50 | 55 |
| 22.5–35 | 60 |
| 15–22.5 | 65 |
| 13.5–15 | 70 |
| 12–13.5 | 77.5 |
| 10.5–12 | 85 |
| 9–10.5 | 92.5 |
| 8–9 | 100 |
| 7–8 | 110 |
| 6–7 | 125 |
| 5–6 | 150 |
| 4–5 | 175 |
| 3–4 | 200 |
| 2–3 | 250 |
| 1–2 | 300 |
| Less than 1 | 400–500 |
These ranges are approximate. Your actual class also depends on the commodity type, handling requirements, and liability considerations.
National Motor Freight Classification and density calculations
The National Motor Freight Classification (NMFC) system, managed by the NMFTA, assigns a code to each commodity. Each NMFC code has a corresponding freight class.
Some NMFC codes are density-based. That means the class changes depending on your shipment's calculated density. Others are fixed regardless of density, based on factors like fragility, liability, or handling difficulty.
To classify your shipment accurately:
- Identify each commodity by its NMFC code.
- Check whether the code uses density-based classification.
- Calculate your density and match it to the class range for that code.
If you're unsure of your NMFC code, your carrier or freight broker can help you identify it. Declaring the wrong class can lead to reclassification fees.
Density calculation for common commodities
Different commodities produce very different densities. Here are some typical examples to help you benchmark your own shipment:
- Machine parts (steel): Often 35+ PCF. Usually class 50.
- Bottled beverages on a pallet: Roughly 20–30 PCF. Typically class 60–70.
- Boxed electronics: Around 8–12 PCF. Often class 85–100.
- Furniture (assembled): About 4–7 PCF. Frequently class 125–175.
- Pillows, foam, or lightweight plastics: As low as 1–4 PCF. Can reach class 200–400.
These are general ranges. Actual density depends on packaging, pallet configuration, and product weight. Always calculate your specific shipment rather than relying on commodity averages.
For a quick reference: the answer will provide your exact PCF once you enter your shipment's weight and dimensions into the calculator above.
FAQs about the density calculator
What is density? Density is mass per unit volume. In freight shipping, it's expressed as pounds per cubic foot. It tells you how heavy a shipment is relative to the space it occupies.
What is the formula for density? Density = Weight ÷ Volume. For freight, divide the weight in pounds by the volume in cubic feet. The result is pounds per cubic foot.
How do you calculate freight density? Measure the shipment's length, width, and height in inches. Multiply them together to get cubic inches. Divide by 1,728 to convert to cubic feet. Then divide the weight in pounds by the cubic feet.
How can I classify my shipment? Calculate your density first. Then look up your commodity's NMFC code. If the code uses density-based classification, match your PCF to the appropriate freight class range. Your carrier can help verify the correct class.
How can I find mass with density and volume? Multiply density by volume. If you know an object's density is 32.42 pounds per cubic foot and it occupies 2 cubic feet, the mass is 64.84 pounds.
How can I find volume with density and mass? Divide mass by density. If an object weighs 90 pounds and has a density of 7.98 PCF, its volume is approximately 11.28 cubic feet.
How do I find the density of a liquid? Weigh a known volume of the liquid. Divide the weight by the volume. For example, if 1 cubic foot of a liquid weighs 62.4 pounds, its density is 62.4 PCF.
How do I measure the density of an irregular object? For shipping, measure the bounding box: the smallest rectangular shape that fully contains the object. Use those dimensions to calculate cubic feet, then divide the weight by that volume.
What does 1,728 represent in the formula? There are 1,728 cubic inches in one cubic foot (12 × 12 × 12). Dividing total cubic inches by 1,728 converts your measurement to cubic feet.
Do I include pallet weight in the calculation? Yes. Include the weight of the pallet (approximately 30 pounds for a standard wood pallet) and all packaging. Carriers weigh the entire shipment, not just the product.