kilo-


This article describes the SI prefix. For other meanings, see Kilo.
Sister project Look up kilo- in Wiktionary, the free dictionary.

Kilo (symbol: k) is a prefix in the SI and other systems of units denoting 103 or 1,000. For example:

It was adopted by Antoine Lavoisier and his group in 1795. The metric system was introduced officially in France in 1799, and the General Conference on Weights and Measures was formed in 1875.

It comes from the Greek χίλιοι ("khilioi"), meaning thousand.

SI prefixes
1000m 10n Prefix Symbol Since[1] Short scale Long scale Decimal
10008 1024 yotta Y 1991 Septillion Quadrillion 1000000000000000000000000
10007 1021 zetta Z 1991 Sextillion Trilliard 1000000000000000000000
10006 1018 exa E 1975 Quintillion Trillion 1000000000000000000
10005 1015 peta P 1975 Quadrillion Billiard 1000000000000000
10004 1012 tera T 1960 Trillion Billion 1000000000000
10003 109 giga G 1960 Billion Milliard 1000000000
10002 106 mega M 1960 Million 1 000 000
10001 103 kilo k 1795 Thousand 1000
10002⁄3 102 hecto h 1795 Hundred 100
10001⁄3 101 deca da 1795 Ten 10
10000 100 (none) (none) NA One 1
1000−1⁄3 10−1 deci d 1795 Tenth 0.1
1000−2⁄3 10−2 centi c 1795 Hundredth 0.01
1000−1 10−3 milli m 1795 Thousandth 0.001
1000−2 10−6 micro µ 1960[2] Millionth 0.000001
1000−3 10−9 nano n 1960 Billionth Milliardth 0.000000001
1000−4 10−12 pico p 1960 Trillionth Billionth 0.000000000001
1000−5 10−15 femto f 1964 Quadrillionth Billiardth 0.000000000000001
1000−6 10−18 atto a 1964 Quintillionth Trillionth 0.000000000000000001
1000−7 10−21 zepto z 1991 Sextillionth Trilliardth 0.000000000000000000001
1000−8 10−24 yocto y 1991 Septillionth Quadrillionth 0.000000000000000000000001
  1. The metric system was introduced in 1795 with six prefixes. The other dates relate to recognition by a resolution of the CGPM.
  2. The 1948 recognition of the micron by the CGPM was abrogated in 1967.

Use in computing

In binary computing, kilo does not always denote 1,000 but is sometimes equal to 1,024 (210), most often when discussing memory and file sizes. See binary prefix for more details.

sex





stock | retire | vm
Why are we here?
All text is available under the terms of the GNU Free Documentation License
This page is cache of Wikipedia. History