This paper shows the design of the newly made ‘n’ bit incrementer and decrementer circuit using quantum-dot cellular automata (QCA). Ripple carry incrementer and decrementer are crucial for performing two numbers’ increment or decrement operation. This paper outlines the design of a novel low power ripple carry incrementer and ripple carry decrementer circuit based on QCA. The proposed ripple carry incrementer and ripple carry decrementer circuit are achieved with a new layout of the XOR gate, AND gate, and half adder circuit. This newly designed XOR and half adderare compared with state-of-the-artdesigns.QCA Designer 2.0.3 is used to design the circuits. The simulation results of 4-bit, 8-bit, and 16-bit incrementer and decrementer circuits are by the theoretical results.