Did you ever wonder that you had bought a 120 GB HDD but the computer showed it as a 111 GB HDD. And where did the rest of the space eventually disappear? Well nothing disappeared and even the manufacturer didnt make a fool of you.
This happens because there is a slight difference between the way the computer and the manufacturer calculate the HDD size.
One GB according to Computer Science Terminology
8bit = 1 Byte
1024 Bytes = 1 Kbyte
1024 KBytes=1MByte
1024 Mbytes=1GByte
One GB according to Manufacturers
8bit = 1 Byte
1000 Bytes = 1 Kbyte
1000 KBytes=1MByte
1000 Mbytes=1GByte
A we see that greater the hard drive size the larger is the number of missing GBs…
| Theoretical Value | Practically what we get |
| 1 GB | 0.931 GB |
| 10 GB | 9.31 GB |
| 20 GB | 18.62 GB |
| 40 GB | 37.25 GB |
| 80 GB | 74.50 GB |
| 120 GB | 111.75 GB |
| 160 GB | 149.01 GB |
| 250 GB | 232.83 GB |
| 320 GB | 298.02 GB |
| 500 GB | 465.66 GB |
The manufacturers state that they call one GB as 109 and not 1024x1024x1024