In computing, kilo does not always exactly denote 1000 but is usually equivalent to 1024 (210), most often when denoting storage. For example, a kilobyte is 1024 bytes, not 1000 bytes. However, kilo and mega often have their traditional SI meanings when referring to rates of data transfer. For instance, 56 kilobits per second is 56,000 bits per second, not 57,344 bits per second.
A common convention is to use k for 1000 and K for 1024.
Kilo is also the letter K in the NATO phonetic alphabet