Base units
| Quantity | Name of unit | Symbol |
|---|---|---|
| length | meter | m |
| mass | kilogram | kg |
| time | second | s |
| electric current | ampere | A |
| thermodynamic temperature (1) | kelvin | K |
| amount of substance | mole | mol |
| luminous intensity | candela | cd |
Supplementary units
| Quantity | Name of unit | Symbol |
|---|---|---|
| plane angle | radian | rad |
| solid angle | steradian | sr |
Derived units expressed as a compound of the base units
| Quantity | Name of unit | Symbol |
|---|---|---|
| area | square meter | m2 |
| volume | cubic meter | m3 |
| speed, velocity | meter per second | m/s |
| acceleration | meter per second squared | m/s2 |
| mass density | kilogram per cubic meter | kg/m3 |
| specific volume | cubic meter per kilogram | m3/kg |
| wave number | reciprocal meter | m-1 |
| electric current density | ampere per square meter | A/m2 |
| magnetic field strength | ampere per meter | A/m |
| amount -of-substance concentration | mole per cubic meter | mol/m3 |
| luminance | candela per square meter | cd/m2 |
Derived units with special names and symbols
| Quantity | Name of unit | Symbol | Expressions in terms of base units, supplementary units and other SI units |
|---|---|---|---|
| frequency | hertz | Hz | 1 Hz = 1 s-1 |
| force | newton | N | 1 N = 1 kg･m/s2 |
| pressure, stress | pascal | Pa | 1 Pa = 1 N/m2 |
| power, rate of production, motive power, electric power | watt | W | 1 W = 1 J/s |
| Celsius temperature | degree Celsius, or degree | ℃ | t℃ = TK-273.15K |
| energy, work, quantity of heat | joule | J | 1J = 1 N･m |
| electric charge, quantity of electricity | coulomb | C | 1C = 1 A･s |
| electric potential, electric potential difference, voltage, electromotive force | volt | V | 1V = 1 J/C |
| electric capacitance | farad | F | 1F = 1 C/V |
| (electric) resistance | ohm | 1Ω = 1 V/A | |
| (electric) conductance | siemens | S | 1S = 1Ω-1 |
| magnetic flux | weber | Wb | 1Wb = 1 V･s |
| magnetic flux density, magnetic induction | tesla | T | 1T = 1Wb/m2 |
| inductance | henry | H | 1H = 1 Wb/A |
| luminous flux | lumen | lm | 1lm = 1cd･sr |
| illuminance | lux | lx | 1lx = 1 lm/m2 |
| Factor | Prefix | |
|---|---|---|
| Name | Symbol | |
| 1018 | exa | E |
| 1015 | peta | P |
| 1012 | tera | T |
| 109 | giga | G |
| 106 | mega | M |
| 103 | kilo | k |
| 102 | hecto | h |
| 10 | deka | da |
| 10-1 | deci | d |
| 10-2 | centi | c |
| 10-3 | milli | m |
| 10-6 | micro | |
| 10-9 | nano | n |
| 10-12 | pico | p |
| 10-15 | femto | f |
| 10-18 | atto | a |
Units accepted for use with the SI because of their practical importance
| Quantity | Name | Symbol | Definition |
|---|---|---|---|
| time | minute hour day |
min h d |
1 min = 60s 1 h = 60min 1 d = 24h |
| plane angle | degree of arc minute of arc second of arc |
0 ' " |
10= (n/180)rad 1 " = (1/60)0 1" = (1/60)' |
| volume | liter | l, L (N.B.) | 1l= 1 dm3 |
| mass | metric ton | t | 1t = 103kg |
N.B. L may be used where l may be confused with something else.
Units accepted for use with the SI in specialist areas
| Quantity | Name | Symbol | Definition |
|---|---|---|---|
| fluid pressure | bar | bar | 1 bar = 105Pa |
| energy | electronvolt | eV | (modern version) 1eV = 1.6021892 X 10-19J |
| atomic mass | unified atomic mass unit | (modern version) 1μ = 1.6605655 X 10-27kg | |
| length | astronomical unit | AU pc |
1 AU = 149597.870 X 106m (modern version) 1pc = 206 265 AU = 30857 X 1012m |
| Next ＞＞ |
