Created and maintained by a nonprofit organization called the National Motor Freight Traffic Association (NMFTA), National Motor Freight Classification (NMFC) is a classification system used for interstate, intrastate, and foreign commerce movement of LTL shipments. You can learn more on our freight classes pages.
If the couch you are shipping has not been assembled yet and you are shipping various components that you can use freight class 250. If you are shipping a complete product then you should use freight class 175.
Some items, such as car transmissions, have a specific class no matter how heavy or big they are. This is called a fixed class. Items can be assigned a fixed class if the value and transportability very rarely change.