Two's complement of 11

The 8-bit two's complement of 11 is 11110101, the bit pattern that represents -11 (minus 11). Written as a signed 8-bit number, 11 itself is 00001011.

Invert and add 1

Here is the two's complement of 11 at 8 bits, step by step (invert the bits of 11 and add 1):

1. Write 11 in 8-bit binary: 00001011.
2. Invert every bit (the one's complement): 11110100.
3. Add 1: 11110101.

11 at 4, 8, and 16 bits

A dash means 11 (or its negation) is outside that width's signed range: 4-bit two's complement holds -8 to 7, 8-bit holds -128 to 127, and 16-bit holds -32768 to 32767.

Reading 11 as a binary pattern

The digits of 11 are all 0s and 1s, so "two's complement of 11" often means the 2-bit binary number 11 itself, not the decimal 11. As a signed 2-bit value that pattern is -1. Its two's complement is 01: invert 11 to 00 and add 1.

So negating the pattern turns -1 into 1: the two's complement of 11 is 01.

Convert any number

Two's complement is how computers store signed integers, so one adder can both add and subtract. Read the full two's complement lesson, or convert any value at 8, 16, or 32 bits with the two's complement calculator.

Frequently asked

What is the two's complement of 11?

The 8-bit two's complement of 11 is 11110101, the bit pattern for -11. You get it by writing 11 in binary (00001011), inverting every bit (11110100), then adding 1.

How do you write 11 in two's complement?

11 in 8-bit two's complement is 00001011. Positive numbers are identical to plain binary, so no inverting is needed. At 16 bits it is 0000000000001011.

What is the two's complement of 11 (as binary)?

Reading 11 as a 2-bit binary pattern, its two's complement is 01: invert 11 to 00 and add 1. As signed values, that negates -1 to 1.