So you just purchased a new hard drive and when you go to format it, the size reported is smaller than what you expect. Or maybe you got bored and looked into the hardware information and were surprised to see the hard drive being reported in a smaller number. Before you pick up the phone to call your lawyer, you might want to read on.

Basically, the problem exists due to the fact that during the infancy of computers, people in the industry decided that they would call 1024 bytes a kilobyte although the prefix ‘kilo’ should refer to 1000 in the manner a kilometer refers to 1000 meters and kilogram refers to 1000 grams. At first the difference was negligible as drives were still only a few hundred megabytes in size but as they got into gigabytes the difference in size became much more apparent. To make it easier to understand, let’s use beer as an example. A standard can is 355ml. Using the calculations used for bytes (355/1024); it would mean that you’re getting only 347ml. That’s only a difference of 8ml…. not a big deal. Now let’s say you buy a 50 liter (50,000ml) keg. Once again, using the byte calculation, it would mean you’re getting 48.828 liters. That’s a difference of over a liter. This kind of difference would probably be a big issue if you just spent a pretty penny on a keg of your favorite beer. More details on the hard drive size calculating methods can be found from the link below:

Seagate Article

So who’s in the right is a matter of interpretation. There have even been efforts to have binary prefixes written as Ki for kibi (1024), Mi for mebi (1024^2), Gi for gibi (1024^3) and so on to distinguish between the two. Unfortunately, the new measure has not been well accepted by the industry.

Honestly, the problem was due to people deciding for the sake of convenience, to use a measure that was easily recognizable without considering the future implications of their decision. So you have the hard drive manufacturers adopting the measure of 1 kB = 1000 bytes while computer programmers adopting the measure of 1 kB = 1024 bytes. Personally, unless we dump the decimal system and all adopt binary as the standard method for counting, I’m siding with the drive manufacturers as I was educated with the explanation that a kilo is the prefix for a 1000 not 1024.