Methodology and sources
How LTL Math calculators work, and where their numbers come from.
How the calculators are built
Each calculator runs entirely in your browser; nothing you type is sent anywhere. Results are rounded only for display, and every page shows the formula it uses and a worked example you can check by hand.
The freight class density scale
Freight class estimates use the 13-tier density scale that the National Motor Freight Traffic Association (NMFTA) put into the National Motor Freight Classification with Docket 2025-1, effective July 19, 2025. Density is weight in pounds divided by volume in cubic feet, measured on the shipment as it ships, pallet included. The scale was last checked on 28 October 2026 against DTS and the NMFTA.
Some items keep their own class whatever their density, because of handling, stowability or liability. LTL Math does not publish NMFC item numbers: that data is licensed by the NMFTA. Every class shown here is an estimate, and the carrier assigns the final class.
| Density (lb per cu ft) | Estimated class |
|---|---|
| Less than 1 | 400 |
| 1 to under 2 | 300 |
| 2 to under 4 | 250 |
| 4 to under 6 | 175 |
| 6 to under 8 | 125 |
| 8 to under 10 | 100 |
| 10 to under 12 | 92.5 |
| 12 to under 15 | 85 |
| 15 to under 22.5 | 70 |
| 22.5 to under 30 | 65 |
| 30 to under 35 | 60 |
| 35 to under 50 | 55 |
| 50 or more | 50 |
By calculator
Corrections
If you find an error, tell us and it will be checked and fixed.