Mega is a unit prefix in metric systems of units denoting a factor of one million (106 or 1000000). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. Mega comes from Ancient Greek: μέγας, romanized: mégas, lit. 'great'. [1]
When units occur in exponentiation, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation.
In some fields of computing, mega may sometimes denote 1048576 (220) information units, for example, a megabyte, a megaword, but denotes 1000000 (106) units of other quantities, for example, transfer rates: 1megabit/s = 1000000 bit/s. In the case of 3½-inch floppy disks, sizes were given in megabytes of 1000KB or 1024000 bits. [2] The prefix mebi- has been suggested as a prefix for 220 to avoid ambiguity.
Prefix | Base 10 | Decimal | Adoption [nb 1] | |
---|---|---|---|---|
Name | Symbol | |||
quetta | Q | 1030 | 1000000000000000000000000000000 | 2022 [3] |
ronna | R | 1027 | 1000000000000000000000000000 | |
yotta | Y | 1024 | 1000000000000000000000000 | 1991 |
zetta | Z | 1021 | 1000000000000000000000 | |
exa | E | 1018 | 1000000000000000000 | 1975 [4] |
peta | P | 1015 | 1000000000000000 | |
tera | T | 1012 | 1000000000000 | 1960 |
giga | G | 109 | 1000000000 | |
mega | M | 106 | 1000000 | 1873 |
kilo | k | 103 | 1000 | 1795 |
hecto | h | 102 | 100 | |
deca | da | 101 | 10 | |
— | — | 100 | 1 | — |
deci | d | 10−1 | 0.1 | 1795 |
centi | c | 10−2 | 0.01 | |
milli | m | 10−3 | 0.001 | |
micro | μ | 10−6 | 0.000001 | 1873 |
nano | n | 10−9 | 0.000000001 | 1960 |
pico | p | 10−12 | 0.000000000001 | |
femto | f | 10−15 | 0.000000000000001 | 1964 |
atto | a | 10−18 | 0.000000000000000001 | |
zepto | z | 10−21 | 0.000000000000000000001 | 1991 |
yocto | y | 10−24 | 0.000000000000000000000001 | |
ronto | r | 10−27 | 0.000000000000000000000000001 | 2022 [3] |
quecto | q | 10−30 | 0.000000000000000000000000000001 | |
|
Origin: A borrowing from Greek. Etymon: Greek μεγα-. ... Forming scientific and technical terms with the sense 'very large', 'comparatively large', or (esp. in Pathol.) 'abnormally large', often having correlatives beginning micro-, and sometimes also synonyms beginning macro-.
Mega is a unit prefix in metric systems of units denoting a factor of one million (106 or 1000000). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. Mega comes from Ancient Greek: μέγας, romanized: mégas, lit. 'great'. [1]
When units occur in exponentiation, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation.
In some fields of computing, mega may sometimes denote 1048576 (220) information units, for example, a megabyte, a megaword, but denotes 1000000 (106) units of other quantities, for example, transfer rates: 1megabit/s = 1000000 bit/s. In the case of 3½-inch floppy disks, sizes were given in megabytes of 1000KB or 1024000 bits. [2] The prefix mebi- has been suggested as a prefix for 220 to avoid ambiguity.
Prefix | Base 10 | Decimal | Adoption [nb 1] | |
---|---|---|---|---|
Name | Symbol | |||
quetta | Q | 1030 | 1000000000000000000000000000000 | 2022 [3] |
ronna | R | 1027 | 1000000000000000000000000000 | |
yotta | Y | 1024 | 1000000000000000000000000 | 1991 |
zetta | Z | 1021 | 1000000000000000000000 | |
exa | E | 1018 | 1000000000000000000 | 1975 [4] |
peta | P | 1015 | 1000000000000000 | |
tera | T | 1012 | 1000000000000 | 1960 |
giga | G | 109 | 1000000000 | |
mega | M | 106 | 1000000 | 1873 |
kilo | k | 103 | 1000 | 1795 |
hecto | h | 102 | 100 | |
deca | da | 101 | 10 | |
— | — | 100 | 1 | — |
deci | d | 10−1 | 0.1 | 1795 |
centi | c | 10−2 | 0.01 | |
milli | m | 10−3 | 0.001 | |
micro | μ | 10−6 | 0.000001 | 1873 |
nano | n | 10−9 | 0.000000001 | 1960 |
pico | p | 10−12 | 0.000000000001 | |
femto | f | 10−15 | 0.000000000000001 | 1964 |
atto | a | 10−18 | 0.000000000000000001 | |
zepto | z | 10−21 | 0.000000000000000000001 | 1991 |
yocto | y | 10−24 | 0.000000000000000000000001 | |
ronto | r | 10−27 | 0.000000000000000000000000001 | 2022 [3] |
quecto | q | 10−30 | 0.000000000000000000000000000001 | |
|
Origin: A borrowing from Greek. Etymon: Greek μεγα-. ... Forming scientific and technical terms with the sense 'very large', 'comparatively large', or (esp. in Pathol.) 'abnormally large', often having correlatives beginning micro-, and sometimes also synonyms beginning macro-.