Lux (lx)

Lux (lx) is the unit of measurement of illuminance and is defined as the photometric illumination produced by a luminous flux of 1 lumen when uniformly distributed over an area of 1 square meter: 1lx = 1lm/m²

Representation of the lux unit of measurement.

Alternative Definition

Since 1 candela (cd) equals 1 lumen per steradian (lm/sr) and an area of 1 m² at a distance of 1 meter corresponds to a solid angle of 1 sr, it can be said that 1 lux is the illuminance at a distance of 1 meter from a point light source with a luminous intensity of 1 candela. Back