Measurements are for an average size model.
Yours will be larger or smaller depending on the specific vehicle.

1/18 is our most popular scale. It offers the most detail at an affordable size, models ranging in length from 8" for a vehicle the size of a VW Bug, to over 12" for a late 1950's Cadillac.

1/18 means that 1" of the model represents 18" of the real vehicle. So logically, a car that is 18' in length will be 12" in 1/18 diecast. Make sense?