Why computer recognizes hard drive size to be less than whats printed on box

Once in a while, everyone must’ve been confused and intrigued about the hard drive sizes. The don’t give what the promise. I still remember when I bought my first 20GB harddisk and was surprised to see only 18.6 GB. I was about to return it back claiming it was damaged when I researched and found out why.

Here’s the explanation.
HDD manufacturers label and make the HDDs using 1000 bytes = 1kb (kilobyte), 1000kb = 1mb (megabyte) and so on. But according to computers 1024 bytes = 1 kb, 1024 kb = 1 mb and so on.
So, computer always will recognize less space due to different measurement values.

Take the analogy of money here. Say, you have a 100 cents, which is 1$ for normal people. Now some crazy guy believes that 120 cents make 1$. For him you won’t have a complete dollar, you’ll have 0.833$. Same is the case with computers. HDD manufacturers are the normal guys, while computer is the crazy one :D. Okay, that was a silly one but you get the drift.

For calculating actual disk space of any size of disk. Do this:
If you have a 40 GB HDD, calculate its equivalent in bytes using 1000 bytes =1 kb concept. As this is used by manufacturers.

40 GB = 40,000 MB = 40,000,000 KB = 40,000,000,000 bytes.

By this we get actual bytes. Now convert it into actual amount of HDD by dividing it with 1024.

40,000,000,000 bytes = 39062500 kb = 38146.97265625 mb = 37.252902984619140625 GB.

So this is the actual amount of GBs we get when buying 40GB HDD.

Same is the case with Flash Pen Drives.

Its not so complex mathematics as it seems. Its just due to huge figures.

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