This is essentially the same as for normal binary numbers but with different column headings but we still just add up all the column headings where there is a 1 in the column.
For our example let's convert the decimal number 01011100 in 8 bit binary with 4 bits either side of the decimal point to a decimal number with a fractional part.
| 8 | 4 | 2 | 1 | .5 | .25 | .125 | .0625 | Total |
|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5.75 |
4 + 1 + 0.5 + 0.25 = 5.75
Be sure to read any question on fixed point numbers carefully to check how many bits are used for the whole number part and how many for the fractional part. Also keep an eye out for whether the question says the number is in two's compliment or not.
Click the button to get a number to convert
| -8 | 4 | 2 | 1 | .5 | .25 | .125 | .0625 | Total |
|---|---|---|---|---|---|---|---|---|