Lever is a simple machine containing a beam pivoted to a fixed end by fulcrum. The amount of force used internally by this simple machine is called as mechanical advantage of lever. There are three classes of levers : first, second and third. The ratio of the effort arm and load arm is the MA of lever.
Even though the position of the fulcrum varies for the three different types of classes, the formula to find the MA for all the three class of levers are same .