The lux (abbreviated lx) is the SI derived unit of illuminance or illumination. It is equal to one lumen per square metre.

  • sunlight on an average day ranges from 32,000 to 100,000 lux
  • TV studios are lit at about 1,000 lux
  • a bright office has about 400 lux of illumination
  • moonlight represents about 1 lux
  • starlight measures a mere 0.00005 lux


Lux is also the name of a commune in the Côte-d'Or département in France.