SI Prefixes List
An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. The abbreviation SI is from the French language name Système International d’Unités (also known as International System of Units). SI prefixes are used to reduce the quantity of zeroes in numerical equivalencies. Twenty SI prefixes are available to combine with units of measure. On this page you can see SI Prefix Chart.SI Prefixes List
Below, you can find the chart of 24 prefixes introduced and governed by
Bureau International des Poids et Mesures (eng. International Bureau of Weights and Measures )
.The abbreviation SI is from the French language name Système International d’Unités
(eng: International System of Units )
| Prefix | Symbol | 10n | Long/Short Scale |
|---|---|---|---|
| yotta (gr. okto - eight) | Y | 1024 | Quadrillion/Septillion |
| zetta (lat. septem - seven) | Z | 1021 | Trilliard/Sextillion |
| exa (gr. ex - six) | E | 1018 | Trillion/Quintillion |
| peta (gr. penta - five) | P | 1015 | Billiard/Quadrillion |
| tera (gr. teras – monster) | T | 1012 | Billion/Trillion |
| giga (gr. gigas – giant) | G | 109 | Milliard/Billion |
| mega (gr. megas – great) | M | 106 | Million/Million |
| kilo (gr. khilioi – thousand) | k | 10³ | Thousand/Thousand |
| hecto (gr. hekaton – hundred) | h | 10² | Hundred/Hundred |
| deca (gr. deka – ten) | da | 101 | Ten/Ten |
| 100 | One/One | ||
| decy (lat. decimus – tenth) | d | 10-1 | Tenth/Tenth |
| centy (lac. centum – hundredth) | c | 10-2 | Hundredth/Hundredth |
| milli (lac. mille – thousand) | m | 10-3 | Thousandth/Thousandth |
| mikro (gr. mikros – small) | µ | 10-6 | Millionth/Millionth |
| nano (gr. nanos – dwarf) | n | 10-9 | Milliardth/Billionth |
| pico (it. piccolo – small) | p | 10-12 | Billionth/Trillionth |
| femto (den. femten – fifteen) | f | 10-15 | Billiardth/Quadrillionth |
| atto (den. atten – eighteen) | a | 10-18 | Trillionth/Quintillionth |
| zepto (lat. septem - seven) | z | 10-21 | Trilliardth/Sextillionth |
| yokto (gr. okto - eight) | y | 10-24 | Quadrillionth/Septillionth |
Short And Long Scale
In most English-speaking countries short scale is used. In short scale
Billion prefix (109) is giga, Trillion prefix (1012) is tera,
Billionth prefix (10-9) is nano, Trillionth prefix (10-12 is pico, and so on.
In most European countries long scale is used. In long scale Billion prefix (1012) is tera, Trillion prefix (1018) is exa, Billionth prefix (10-12) is pico, Trillionth prefix (10-18) is atto, and so on.
In most European countries long scale is used. In long scale Billion prefix (1012) is tera, Trillion prefix (1018) is exa, Billionth prefix (10-12) is pico, Trillionth prefix (10-18) is atto, and so on.
Prefixes In Computing
Prefixes K,M,G,T,P (kilo,mega,giga,tera,peta) are commonly used in computing,
where they are applied to information and storage units. Since informational systems are based
on power of 2, this led to following meaning of prefixes in computer science:
See also: Data Capacity Converter
| Prefix | Symbol | 2n | Decimal Value |
|---|---|---|---|
| kilo | K | 210 | 1 024 |
| mega | M | 220 | 1 048 576 |
| giga | G | 230 | 1 073 741 824 |
| tera | T | 240 | 1 099 511 627 776 |
| peta | P | 250 | 1 125 899 906 842 624 |
