Kilo? kilo?

Kilo is one of the prefix multipliers that is used to quantify things in computing and telecommunications ,bytes or bits, or electronics or physics, for example ohm or Hz. Each prefix multiplier consists of a one-letter abbreviation and the prefix that it stands for. Kilo is represented by the letter K or k.

Sometimes we see kilo represented by a upper case K, Kbytes or Kbits; sometimes its in lower case, kHz. Should it be always upper case or always lower case?

In communications, electronics, and physics, the prefix multipliers are defined in powers of 10 such as frequency, kHz, data speed, kbps, and resistance value, kΩ. For IT and data storage, the prefix multipliers are mostly defined in powers of 2 such as KB (KByte).