One's Complement Calculator

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

This calculator also provides a comprehensive step-wise process of finding 1s complement. You can enter up to 8-bit binary numbers.

Note: Do not add space between digits of 8-bit numbers.

What is one’s complement?

One’s complement can be defined as the inverse of a binary number. By inverse, it does not mean to add 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.