The HDD vendors don’t lie about how many bytes are available – they just count them differently. They use base 10 counting and consider a Kb as 1000 bytes, etc… This gives you a larger reported capacity when comparing to base 2 counting (1024 bytes in a Kb).

Since our computers use binary math (base 2 math), they count 1024 bytes in a Kb, thus you end up with less HDD space than the manufacturer claims. If you check the HDD labels though, you should clearly see that they state how they calculate the total drive size.

If you wanted even more mind-boggling entertainment, you can figure out how much MORE space you’ve lost because of how your HDD is formatted. When you format your drive, it “chops it up” in to a bunch of clusters, which you can configure the size of when you format (default for NTFS is 4Kb). When you write a file to disk, it allocates disk space in clusters rather than individual bytes. This means if you save a 60 byte file, it actually takes up an entire 4Kb cluster – you’ve just wasted 4036 bytes!