Enter the decimal number you want to convert and the number of bits you need and click the ‘Convert’ button to get the one’s complement binary number, or enter the one’s complement binary number and click the ‘Convert’ button to get the decimal number.

See also our Two’s Complement Calculator.

One’s complement is a method for representing signed numbers in binary number system. When we want to convert a binary number to one’s complement we revert each bit of this number, meaning 1 changes to 0 and 0 changes to 1. For positive numbers the leftmost bit is 0 and for negative numbers the leftmost bit is 1. The number zero has two representation: +0 (positive zero) and −0 (negative zero).