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

However, this value is not indicated on packaging. The reason is that a key variable affects lux calculations: the distance to the light source. Since this distance can vary for each user, a general value cannot be given. The other light units shown on packaging therefore provide more useful information about the light.

To give you 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 respect is the candela. Candela is the base unit for light calculations.