Lux (Latin for light) is the amount of lumens emitted onto a surface of 1 m². It is also known as the illuminance. One lux is equal to 1 lumen per m².

However, this value is not indicated on the packaging of lamps. The reason for this is that an important variable plays a role in the calculation of lux: the distance to the light source. Because this distance can vary for each user, it is not possible to provide a general value. The other light units that are on the packaging therefore provide better information about the light.

To give an idea of lux, here are some examples:

• Sunlight: 100,000 lux

• Daylight: 15,000 lux

• Full moon: 0.1 lux

A unit that is more universal in this area is the candela. Candela is the base unit in calculations of light.