Freight Class Calculator
Use this free freight class calculator to find the NMFC freight class for your LTL shipment. Enter the total weight and the length, width, and height of your freight, and the calculator instantly shows the shipment volume in cubic feet, the density in pounds per cubic foot, and the matching freight class — so you can quote and book with confidence.
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Enter weight and dimensions to see the freight class.
How to use this calculator
Weigh your shipment (or add up the weights of every box or pallet) and enter the total in pounds. Then measure the freight as it will actually ship — length, width, and height in inches, including the pallet if you use one. The calculator does the rest instantly: it converts the dimensions to cubic feet, divides weight by volume to get density, and looks up the NMFC freight class for that density.
Use the result to sanity-check carrier quotes and to spot misclassification before you book. If a quote assumes a higher class than your density supports, ask the carrier which class they used and why — the difference can be meaningful on a per-hundredweight rate.
How it works
Freight class is driven by density: pounds per cubic foot (lb/ft³). The math is:
Volume = (length × width × height in inches) ÷ 1728 = cubic feet
Density = weight in pounds ÷ cubic feet = lb/ft³
For example, 500 lb in a 48 × 40 × 36 in space: 48 × 40 × 36 = 69,120 in³ ÷ 1728 = 40 ft³, and 500 ÷ 40 = 12.5 lb/ft³. The calculator then matches the density to the standard 18-class NMFC density table — Class 50 for the densest freight (50+ lb/ft³) down to Class 500 for the bulkiest (under 1 lb/ft³), for example 12.5 lb/ft³ lands in the 12–13.5 band, so Class 85:
50+: Class 50 · 35–50: Class 55 · 30–35: Class 60 · 22.5–30: Class 65 · 15–22.5: Class 70 · 13.5–15: Class 77.5 · 12–13.5: Class 85 · 10.5–12: Class 92.5 · 9–10.5: Class 100 · 8–9: Class 110 · 7–8: Class 125 · 6–7: Class 150 · 5–6: Class 175 · 4–5: Class 200 · 3–4: Class 250 · 2–3: Class 300 · 1–2: Class 400 · under 1: Class 500.
Two caveats. First, this is an estimate based on density only: real NMFC classification also weighs stowability, handling, and liability, so a carrier can reclassify your freight and adjust the bill. Second, boundary convention: a density landing exactly on a band boundary is assigned to the higher-density (lower) class. Confirm the final class with your carrier or 3PL before you ship.
Frequently asked questions
How is freight class calculated from density?
Divide the shipment weight in pounds by its volume in cubic feet (length x width x height in inches, divided by 1728). The resulting density in pounds per cubic foot is matched to the NMFC density bands: denser freight gets a lower class number, from Class 50 (50+ lb/ft3) down to Class 500 (under 1 lb/ft3).
What density is Class 100?
In the standard NMFC density table, Class 100 covers shipments with a density of 9 to under 10.5 pounds per cubic foot. It is one of the most common classes for general LTL freight.
Is this freight class calculator accurate?
It is an estimate based on density only. Carriers also consider stowability, handling, and liability, and they can reclassify your freight and adjust the charges. Always confirm the final class with your carrier or 3PL before shipping.
Why does a lower freight class number cost less?
A lower class number means denser freight: more weight in less trailer space, easier to stack, and less damage risk per pound. Bulky, low-density freight takes up room a carrier could sell to someone else, so it is billed at a higher rate per hundredweight.