My 250GB Hard Disk shows 232 GB when Empty!!

Dear Readers,

Most of us who perform day to day computing on a PC are most likely to have a Flash Disk or External hard disk as their source of backup or data transfer from one PC to another. And with the Price per GB at its lowest , in today's market, why not have a bigger storage for a cheaper price than it was a few years back right. So you go out happily and buy a 250 GB hard disk, or any other size for that matter. Now when you get home, and first plug in the hard drive and you open My Computer, you are shocked to see that your 250GB hard disk has 232 GB of free space. And your hard disk is brand new and completely EMPTY !!. and you Ask......

So where is my 18 GB ??

I paid for 250GB and i am getting 232GB, have i been cheated by the seller? Did the seller sell me a fake Hard Disk? Is there a Virus on my computer ?

.... the answer is NO.


This is what happened to your 18GB...

A computer detects 1024 Bytes as 1 KiloByte, but Hard drive manufacturers like Seagate, Samsung, Western Digital, decided it would be easier for consumer if we rounded up that figure by saying 1000 Bytes as 1 KiloByte(KB) or 1 KiloByte(KB) is 1000 Bytes. Trying to simplify things so it would be on the same context as Grams to Kilograms.

These manufacturers can advertise and make decisions themselves, but they cannot force computer to do so. Hence the computer is always recognizing it as 1024 Bytes.

So why do i care!?? ........

You bought a hard disk which was supposed to be 250,000,000,000 Bytes(B)
This is how the computer translates it,

1024 B = 1 KB so 250,000,000,000 Bytes(B) divided by 1024 = 244,140,625 KiloBytes(KB)

1024 KB = 1 MB so 244,140,625 KiloBytes(KB) divided by 1024 = 238,418 MegaBytes(MB)


1024 MB = 1 GB so 238,418 MegaBytes(MB) divided by 1024 = 232 GigaBytes(GB)

So a computer will recognize it as a 232 GB Hard Disk

If you change the value of 1024 to 1000 like most hard drive manufacturers do, you will get the end result as 250GB, which is what they advertise. They tried to simplify the consumer experience when it came to defining the size. Its easier to say 250GB then 232.5 GB

For your reference, here are all the drive/disk sizes with its advertised size vs actual size.

Advertised size :: Actual Size
1 GB :: 0.93 GB
2 GB :: 1.68 GB
4 GB :: 3.72 GB
8 GB :: 7.45 GB
16 GB :: 14.90 GB
32 GB :: 29.80 GB
100GB :: 93.13 GB
120GB :: 111.75 GB
160GB :: 149.01 GB
250GB :: 232.83 GB
320GB :: 298.02 GB
500GB :: 465.66 GB
640GB :: 596.04 GB
1000GB :: 931.32 GB

if i still wasn't clear above, please don't hesitate to write to me, i'll be more than happy to answer your query to the best i can.

Good Day!