Freight class calculator
Enter length, width, height, and weight to see the density and the density-based class.
Freight class
—
- Volume
- — ft³
- Density
- — lb/ft³
- Subprovision
- —
This is a density-based estimate using the 13-subprovision density scale from NMFC Docket NMFC-2025-1. Actual classification is also affected by handling, stowability, and liability characteristics, and the density scale applies only when those issues are absent. Your carrier makes the final call.
| Sub | Density (lb/ft³), as published | Class |
|---|---|---|
| 1 | Less than 1 | 400 |
| 2 | 1 but less than 2 | 300 |
| 3 | 2 but less than 4 | 250 |
| 4 | 4 but less than 6 | 175 |
| 5 | 6 but less than 8 | 125 |
| 6 | 8 but less than 10 | 100 |
| 7 | 10 but less than 12 | 92.5 |
| 8 | 12 but less than 15 | 85 |
| 9 | 15 but less than 22.5 | 70 |
| 10 | 22.5 but less than 30 | 65 |
| 11 | 30 but less than 35 | 60 |
| 12 | 35 but less than 50 | 55 |
| 13 | 50 or greater | 50 |
Enter the length, width, height, and weight of a shipment to get its volume in cubic feet, its density in pounds per cubic foot, and the freight class that density corresponds to under the 13-subprovision scale published in NMFC Docket 2025-1. The calculator also tells you how much weight would move the shipment into the adjacent class in either direction, because a shipment sitting just under a class boundary is often worth re-packing before it is worth re-rating.
How the class is determined here
The scale is a set of half-open density intervals. Each subprovision includes its lower density and excludes its upper density, which is exactly how NMFTA's published table is worded: "6 but less than 8".
The lowest band is open at the bottom (density < 1 lb/ft³) and the highest band is open at the top (density ≥ 50 lb/ft³). There is therefore no density value that fails to fall into a band.
Classification uses the full-precision density. The two-decimal figures shown on screen are for reading only and are never used to pick a band — 7.995 and 8.00 both display as 8.00 but fall in different bands.
When the density scale does not apply
The density scale applies only when a shipment has no unusual handling, stowability, or liability characteristics. A shipment that is fragile, oddly shaped, hazardous, or difficult to stow is classified on those characteristics instead.
Density classification is also subject to NMFC Item (Rule) 170. A density-based answer is an estimate of the density question, not a final classification decision.
Reading the boundary hint
When the result says to add weight to reach a lower class number, reaching that weight exactly is enough: the lower density bound belongs to the denser band.
When the result says to reduce weight to reach a higher class number, the amount shown is not enough on its own. The boundary value belongs to the band you are already in, so you must go below it. That is why the wording is "reduce by more than".
Frequently asked
Why does adding weight sometimes lower my freight class?
Because density is weight divided by volume. At a fixed volume, adding weight raises density, and denser freight sits in a lower class number under the NMFC density scale. Lower class numbers generally rate lower, but your carrier's tariff is what decides the price.
My shipment is exactly on a boundary. Which class applies?
The denser band. The scale intervals are half-open: a density of exactly 8 lb/ft³ falls in the 8-to-10 band, not the 6-to-8 band. NMFTA's published wording for that band is "8 but less than 10".
Is this the same table my carrier uses?
The density bands and class values are the ones published under Docket 2025-1, so they should match. What can differ is whether the density scale applies to your shipment at all, which depends on handling, stowability, and liability characteristics. Your carrier makes the final call.
Why does the result show a class like 92.5?
Because the published scale contains a non-integer class. Subprovision 7, covering 10 up to 12 lb/ft³, is class 92.5. Class values here are treated as text rather than numbers so that 92.5 is never rounded or truncated.