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# One's Complement Calculator

Input the binary number in the one’s (1’s) complement calculator and hit the **‘calculate’ **button.

## 1s Complement Calculator

One's complement calculator is an online tool for converting binary numbers into 1's complement. It finds the complement of a given binary number.

This 1's complement calculator also provides a comprehensive step-wise process of finding 1s complement.

## What is one’s complement?

One’s complement can be defined as the inverse of a binary number. By inverse, it does not mean adding negative signs like decimal numbers (e.g inverse of 4 is -4).

In binary numbers since there are only 2 digits, both of these digits are **1’s complements** of each other. **1 **is the complement of **0 **and **0 **is the complement of **1**.

## How to find one’s complement?

To find 1’s complement of any binary number replace 0’s with 1’s and vice versa. See this example.

**Example:**

What is the one’s complement of the following binary numbers?

- 0101
- 1111
- 1001 1001

**Solution:**

**1st number:**

Binary number = 0101

1’s complement = 1010

**2nd number:**

Binary number = 1111

1’s complement = 0000

**3rd number:**

Binary number = 1001 1001

1’s complement = 0110 0110

## One’s complement table

Decimal number | Binary number | 1’s complement |

1 | 0001 | 1110 |

2 | 0010 | 1101 |

3 | 0011 | 1100 |

4 | 0100 | 1011 |

5 | 0101 | 1010 |

6 | 0110 | 1001 |

7 | 0111 | 1000 |

8 | 1000 | 0111 |

9 | 1001 | 0110 |

10 | 1010 | 0101 |

Use 2’s complement calculator if you want to find two's complement after calculating one's complement of a binary number.

## References

- Wikimedia Foundation. (2022, July 4). One's complement. Wikipedia.