<div align="justify">http://en.wikipedia.org/wiki/Binary_prefix

KB is confusing since it can either mean 1000 or 1024 (2<sup>10</sup>) bytes, depending on what you feel like, basically Or both at the same time, in the case of floppy disks, according to that site.

Windows Explorer uses powers of 1024 though, and in general this is what you want to use when working with file sizes, as 1024 is generally more commonly accepted. You can use the 1000 as an approximation if you want and are too lazy to get a calculator out, but remember it's only an approximation then vBulletin uses powers of 1024 internally as well.

It's a lot safer to use KiB instead of KB (and the binary versions of all the prefixes), since that can <i>only</i> mean 1024 bytes (or the appropriate binary factor) and never be a confusing mix of the two, and removes the need of specifying which of the two you mean exactly as well </div>