The "Ideal Mechanical advantage" (IMA) of given pulley is .
Ideal Mechanical advantage of a system is defined by the ratio of achieved or output force to the implied force. In the pulley system above, output force is the resistant force denoted by . The input force is analogous or equivalent to the effort applied i.e. .
Hence by dividing these two forces we calculate the IMA of the above mentioned pulley system which is .