In this paper, we present a low-power multifunctional circuit for varying operand lengths. In this multifunctional circuit have two blocks 1) Input Selection Block 2) Decision Block. By using these two blocks, we can reduce the delay and the dynamic power due to decrease power supply voltage and frequency. The multifunctional circuit can perform four different operations like priority encoder, increment, 2's complement and decrement. A 64-bit controllable decision block is presented, which can operate on different operands. Our technique is good for multimedia applications because many algorithms function on operands of changing data sizes. © 2013 IEEE.