How to Calculate Freight Class from Density
Freight class is central to U.S. LTL rating, but density alone is not always the final answer. The current NMFC structure makes density a primary factor for many items while preserving other transportation characteristics.
A practical guide to LTL density, the current NMFC density scale and why actual freight class can differ from a density estimate.
Step 1: measure the handling unit
Measure the greatest outside length, width and height of the pallet, crate or other handling unit as it will be tendered. Include packaging, pallet height and protrusions. Convert the volume to cubic feet.
Step 2: calculate density
Divide the gross weight in pounds by cubic feet. For example, a handling unit occupying 40 ft³ and weighing 500 lb has a density of 12.5 lb/ft³.
Step 3: compare with the current density bands
NMFTA's current 13-sub standard density structure runs from class 400 below 1 lb/ft³ to class 50 at 50 lb/ft³ or greater. A density of 12.5 lb/ft³ falls in the 12 to less-than-15 band, corresponding to class 85 under the density scale.
Why the final class can differ
Handling, stowability, liability and the applicable NMFC item can change the class. Density-based calculators are therefore best used for planning, quote checks and identifying obvious dimension or weight errors. Verify the classification before shipping.
Reviewed September 29, 2026 Carrier-sensitive claims are cross-checked against the source library.
Run the calculation
Estimate density-based NMFC freight class using the current 13-sub density structure and your handling-unit dimensions and weight.