Multiples of bits
Value Metric
1000 kbit kilobit
10002 Mbit megabit
10003 Gbit gigabit
10004 Tbit terabit
10005 Pbit petabit
10006 Ebit exabit
10007 Zbit zettabit
10008 Ybit yottabit
1024 Kbit kilobit Kibit kibibit
10242 Mbit megabit Mibit mebibit
10243 Gbit gigabit Gibit gibibit
10244 - - Tibit tebibit
10245 - - Pibit pebibit
10246 - - Eibit exbibit
10247 - - Zibit zebibit
10248 - - Yibit yobibit

The kilobit is a multiple of the unit bit for digital information or computer storage. The prefix kilo (symbol k) is defined in the International System of Units (SI) as a multiplier of 103 (1 thousand),[1] and therefore,

1 kilobit = 103bits = 1000bits.

The kilobit has the unit symbol kbit or kb.

Using the common byte size of 8 bits, 1 kbit is equal to 125 bytes.

The kilobit is closely related to the metric prefix names to designate binary multiples.

The kilobit is most commonly used in the expression of data rates of digital communication circuits as kilobits per second (kbit/s or kb/s), or abbreviated as kbps,[3] as in, for example, a 56 kbps PSTN circuit, or a 512 kbit/s broadband Internet connection.

The unit symbol kb is typographically similar to unit symbols of the kilobyte, i.e. kB, with an upper case B. The International Electrotechnical Commission (IEC) therefore recommends the symbol bit instead of b. The prefix kilo is often used in fields of computer science and information technology with a meaning of multiplication by 1024 instead of 1000, contrary to international standards, in conjunction with the base unit byte and bit, in which case it is to be written as Ki, with a capital letter K,[4] e.g., 1 Kibit or 1 Kib = 1024 bits. The decimal SI definition, 1 kbit/s = 1000 bit/s, is used uniformly in the context of telecommunication transmission speeds.

See also


  1. ^ SI prefixesThe NIST Reference on Constants, Units, and Uncertainty:
  2. ^ Prefixes for binary multiplesThe NIST Reference on Constants, Units, and Uncertainty:
  3. ^ IEEE information for authors, Appendix A
  4. ^ Prefixes for binary multiplesThe NIST Reference on Constants, Units, and Uncertainty: