| S.No | Half Adder | Full Adder |
| 1. | A combinational circuits that performs the addition of two bits is called a half adder | A combinational circuit that performs the addition of three bits (two bits are significant and one is a previous carry) is called a full adder |
| 2. | The half adder circuits needs two binary inputs and two binary outputs. | It consists of three binary inputs and two binary outputs. |
| 3. | Half adder does not have carry in input. | Full adder has carry in input. |
Full adder circuit diagrams :
