Though there are many free freight class calculators available online, they can be misleading in certain of cases. Often, the NMFC code they generate is based solely on dimensions, weight, density, and value. But, these are not the only factors that matter. An over-reliance on these calculators can lead to costly reclassification charges. Three additional factors determine shipping class: Stowability, Handling, and Liability, and it is important to keep them in mind as well: 

1. Stowability: Does your shipment get along with its neighbors?

Does your shipment have weird dimensions or a hazardous content that make it more difficult for it to be stored and shipped with other cargo? The second it does, an online freight class calculator will probably undershoot your freight class.

2.  Handling: Does you shipment require anything other than a traditional equipment?

Fragility, shape, and packaging are critical here. This metric is concerned with how easy it is to load and unload your shipment. Pallets are the go-to method, and if there are any special handling requirements, the freight class will most likely be different than the density and value suggest. 

3.  Liability: Are there higher than average odds of theft or damage?

Liability comes into play when there is a risk of damage to either your shipment or to those shipped alongside it. For example, if a shipment contains something perishable, explosive, or combustible, freight class will be affected. 

Remember,

There are 18 freight classes in total ranging from 50 to 500. Generally, the higher the freight class, the higher the shipping cost. If one or more of these additional factors comes into play, the code you get from density-value-based calculators can leave you open to nasty surprises. Noting the wrong freight class on the bill of lading can have costly consequences in the form of reclassification fees. 

A full and detailed guide to determining shipping class can be purchased from the National Motor Freight Traffic Association. However, 3PLs are the best line of defense against misclassification. Though their experience and up-to-date industry knowledge, logistics providers are the best positioned to advise shippers on proper classification. 

In conclusion, though density-based calculators are excellent tools for getting a general idea of shipping class and cost, their classifications are not flawless and should be paired with an understanding of the other three factors.