A adder is one of the key hardware blocks in most digital and high performance systems such as FIR filters, digital signal processors and microprocessors etc. With advances in technology, many researchers have tried and are trying to design many types of adder such as ripple carry adder, carry skip adder, carry a look head adder and carry select adder. Among this adder carry select adder is the high speed, low power consumption and hence less area or even combination of them in adder. However area and speed are two conflicting constraints.