One's Complement Calculator

Add the number and click on the 'Calculate' button to find its one’s (1’s) complement.

Input Format:

Decimal

Hex

Binary

Decimal One's Complement = -127 to 127

Decimal

No. of Binary Digits:

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One's Complement Calculator

The One’s Complement Calculator is a digital tool designed to compute the 1’s complement of numbers expressed in binary, decimal, or hexadecimal formats. It works by reversing each bit of the number, turning every 0 into 1 and every 1 into 0.

What is One's Complement?

The one’s complement of a binary number is formed by inverting all bits in its signed representation.

Symbol for One's Complement:

The notation used for 1’s complement is ~, commonly known as the bitwise NOT operator in computer systems.

How to Find One’s Complement?

There are two common approaches to determine the 1’s complement:

1. Manual Method

First convert the given value into binary form.
Flip each bit — change 0 to 1 and 1 to 0.

2. Online Calculator

Enter any number into the One’s Complement Calculator, and it will instantly generate the complemented result without manual conversion.

Examples:

Example 1: Binary Number

Determine the 1’s complement of:

(1100100110010)₂

Solution:

Original number: 1100100110010
Bit inversion: 0011011001101

Example 2: Decimal Number

Find the 16-bit 1’s complement of 85:

Solution:

Convert 85 into binary:
- 85 ÷ 2 = 42 remainder 1
- 42 ÷ 2 = 21 remainder 0
- 21 ÷ 2 = 10 remainder 1
- 10 ÷ 2 = 5 remainder 0
- 5 ÷ 2 = 2 remainder 1
- 2 ÷ 2 = 1 remainder 0
- 1 ÷ 2 = 0 remainder 1
Binary form: 1010101
Invert bits: 0101010
16-bit format: 0000 0000 0101 0101

Example 3: Hexadecimal Number

Compute the 1’s complement of hexadecimal ‘3C’:

Solution:

3 = 0011, C = 1100
Invert bits → 1100 0011

One's Complement Table

Decimal, Binary, 1's Complement, and Hexadecimal Equivalents
Decimal	Binary	1's Complement	Hexadecimal
1	0001	1110	1
2	0010	1101	2
3	0011	1100	3
4	0100	1011	4
5	0101	1010	5
6	0110	1001	6
7	0111	1000	7
8	1000	0111	8
9	1001	0110	9
10	1010	0101	A
11	1011	0100	B
12	1100	0011	C
13	1101	0010	D
14	1110	0001	E
15	1111	0000	F