One lux is equal to one lumen per square metre:
1 lx = 1 lm/m2 = 1 cd•sr•m–2.
Illuminance Example
|
Illuminance |
Example |
| 10−4 lux | Total starlight, overcast sky[2] |
| 0.002 lux | Moonless clear night sky with airglow[2] |
| 0.01 lux | Quarter moon |
| 0.27 lux | Full moon on a clear night[2][3] |
| 1 lux | Full moon overhead at tropical latitudes[4] |
| 3.4 lux | Dark limit of civil twilight under a clear sky[5] |
| 50 lux | Family living room[6] |
| 80 lux | Hallway/toilet[7][8] |
| 100 lux | Very dark overcast day[2] |
| 320–500 lux | Office lighting[9][10][11] |
| 400 lux | Sunrise or sunset on a clear day. |
| 1,000 lux | Overcast day[2]; typical TV studio lighting |
| 10,000–25,000 lux | Full daylight (not direct sun)[2] |
| 32,000–130,000 lux | Direct sunlight |