One's Complement

Flip every bit to find the one's complement. Visualize the transformation and signed interpretation.

How One's Complement Works
Invert every bit: 0→1 and 1→0. In an n-bit system, the range is −(27−1) to +(27−1), which means -127 to 127. Note: one's complement has two representations of zero (+0 and −0).
Original
SIGN0
1
0
1
1
0
1
0
7
6
5
4
3
2
1
0
↓Flip all bits (0→1, 1→0)
One's Complement
SIGN1
0
1
0
0
1
0
1
7
6
5
4
3
2
1
0
Original (unsigned)90
Original (signed 1's comp)+90
1's Complement (unsigned)165
1's Complement (signed)-90
8-bit One's Complement Range
-127
127

Step-by-Step Breakdown

1
Pad input to 8 bits
01011010
2
Flip every bit: 0→1, 1→0, 0→1, 1→0, 1→0, 0→1, 1→0, 0→1
10100101
3
MSB (sign bit) = 1 → negative
Signed value: -90