You need to measure it with the Tailgate up, the 7206 is made for trucks that are 5.' to 6.5 ft. The 7218 Is made for trucks with an 8' long bed. If you have a truck that doesn't meet those specifications Please allow me to refer you to the manufacturer's customer service where they should be able to assist you with this. Here is the contact info: Kodiak Canvas - tel. 801-510-3983, their website is kodiakcanvas.com and their email address is [email protected]