Derived quantities are defined in terms of the seven base quantities via a system of quantity equations. The SI derived units for these derived quantities are obtained from these equations and the seven SI base units. Examples of such SI derived units are given below.
| Derived quantity | Name | Symbol |
|---|---|---|
| area | square meter | m2 |
| volume | cubic meter | m3 |
| speed, velocity | meter per second | m/s |
| acceleration | meter per second squared | m/s2 |
| wave number | reciprocal meter | m-1 |
| mass density | kilogram per cubic meter | kg/m3 |
| specific volume | cubic meter per kilogram | m3/kg |
| 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 |
| mass fraction | kilogram per kilogram, which may be represented by the number 1 | kg/kg = 1 |
For ease of understanding and convenience, 22 SI derived units have been given special names and symbols, as shown below.
| Derived quantity | Name | Symbol | Expression in terms of other SI units | Expression in terms of SI base units |
|---|---|---|---|---|
| plane angle | radian (a) | rad | - | m·m-1 = 1 (b) |
| solid angle | steradian (a) | sr (c) | - | m2·m-2 = 1 (b) |
| frequency | hertz | Hz | - | s-1 |
| force | newton | N | - | m·kg·s-2 |
| pressure, stress | pascal | Pa | N/m2 | m-1·kg·s-2 |
| energy, work, quantity of heat | joule | J | N·m | m2·kg·s-2 |
| power, radiant flux | watt | W | J/s | m2·kg·s-3 |
| electric charge, quantity of electricity | coulomb | C | - | s·A |
| electric potential difference, electromotive force | volt | V | W/A | m2·kg·s-3·A-1 |
| capacitance | farad | F | C/V | m-2·kg-1·s4·A2 |
| electric resistance | ohm |  | V/A | m2·kg·s-3·A-2 |
| electric conductance | siemens | S | A/V | m-2·kg-1·s3·A2 |
| magnetic flux | weber | Wb | V·s | m2·kg·s-2·A-1 |
| magnetic flux density | tesla | T | Wb/m2 | kg·s-2·A-1 |
| inductance | henry | H | Wb/A | m2·kg·s-2·A-2 |
| Celsius temperature | degree Celsius | °C | - | K |
| luminous flux | lumen | lm | cd·sr (c) | m2·m-2·cd = cd |
| illuminance | lux | lx | lm/m2 | m2·m-4·cd = m-2·cd |
| activity (of a radionuclide) | becquerel | Bq | - | s-1 |
| absorbed dose, specific energy (imparted), kerma | gray | Gy | J/kg | m2·s-2 |
| dose equivalent (d) | sievert | Sv | J/kg | m2·s-2 |
| catalytic activity | katal | kat | s-1·mol |
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