The capital letter "K" represents a value of `2^10`, this corresponds to the decimal value 1024. Since number sequences with base 2 are used exclusively in digital technology, memory sizes or transmission rates are generally specified in KB or KByte.
The "International System of Units"( SI) standardized by the International Electrotechnical Commission( IEC), which was adopted by NIST, provides for the value `2^10`, i.e. the capital "K", as prefix the kibi( Ki). One kibibit thus corresponds to 1,024 bits.