Two's complement of 256
The 16-bit two's complement of 256 is 1111111100000000, the pattern for -256. Because 256 is larger than 127 it does not fit in a signed 8-bit byte, so as a positive signed value it needs 16 bits: 0000000100000000.
Invert and add 1
Here is the two's complement of 256 at 16 bits, step by step (invert the bits of 256 and add 1):
- Write 256 in 16-bit binary:
0000000100000000. - Invert every bit (the one's complement):
1111111011111111. - Add 1:
1111111100000000.
256 at 4, 8, and 16 bits
| Width | 256 as a signed number | Two's complement of 256 |
|---|---|---|
| 4-bit | — | — |
| 8-bit | — | — |
| 16-bit | 0000000100000000 | 1111111100000000 |
A dash means 256 (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.
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.
Want to see two's complement do real work? Open the lab and wire a subtractor from an adder and inverters, or follow the free course from a transistor up to an 8-bit CPU.
Open the two's complement calculator →Frequently asked
What is the two's complement of 256?
The 16-bit two's complement of 256 is 1111111100000000, the bit pattern for -256. You get it by writing 256 in binary (0000000100000000), inverting every bit (1111111011111111), then adding 1.
How do you write 256 in two's complement?
256 does not fit in signed 8 bits (which stop at 127). In 16-bit two's complement it is 0000000100000000.
What is 256 in 16-bit two's complement?
256 in 16-bit two's complement is 0000000100000000. Two's complement sign-extends a shorter value by copying the sign bit to the left, so the value is unchanged from its 16-bit form.