| Quantity | Symbol | Unit(s) |
| Wavelength | λ | 1 nanometer = 1 nm = 10-9 m 1 Ångstrøm = 1 Å = 10-10 m |
| Power | P | 1 Watt = 1 W |
| Solid angle | Ω | 1 steradian = 1 sr |
| Radiant power or radiant flux | Φe | 1 Watt = 1 W |
| Radiant intensity | Ie | 1 W sr-1 |
| Radiance | Le | 1 W sr-1 m-2 |
| Irradiance | Ee | 1 W m-2 |
| Radiant exitance |
Me Ee |
1 W m-2 1 W m-2 |
| Luminous flux | Φv |
1 lumen = 1 lm photopic: 1 lm corresponds to Φe = 1 / 683 W at λm = 555 nm |
| Luminous intensity | Iv | 1 candela = 1 cd = 1 lm / sr |
| Luminance | Lv | 1 lm sr-1 m-2 = 1 cd m-2 = 1 nit 1 stilb = 1 sb = 1 cd m-2 1 apostilb = 1 asb = 1 / π cd m-2 1 lambert = 1 L = 104 / π cd m-2 1 foot-lambert = 1 fl = 3.426 cd m-2 |
| Illuminance | Ev | 1 lux = 1 lx = 1 lm m-2 1 phot = 1 ph = 104 lx 1 foot-candle = 1 fc = 1 lm ft-2 = 10.764 lx |
| Luminous exitance |
Mv Ee |
1 lm m-2 1 W m-2 |
| Spectral radiant power | Φλ(λ) | 1 W nm-1 |
| Spectral radiant intensity | Iλ(λ) | 1 W sr-1 nm-1 |
| Spectral radiance | Lλ(λ) | 1 W sr-1 m-2 nm-1 |
| Spectral irradiance | Eλ(λ) | 1 W m-2 nm-1 |
| Spectral radiant exitance |
Mλ(λ) Ee |
1 W m-2 1 W m-2 |
Please note: Units in italics are not SI units, not consistent with CIE regulations and should not be used!