Lux (lx)
SI unit of illuminance: one lumen per square meter. Office lighting is typically around 500 lx.
What is a lux?
- Symbol
- lx
- Quantity
- Illumination
- Unit system
- SI
- Definition
- SI unit of illuminance: one lumen per square meter. Office lighting is typically around 500 lx.
- Exact
- Yes, the value is exact by definition
- Source
- SI Brochure, 9th edition (BIPM, 2019)
Common applications
The standard unit for light levels in lighting design, workplace lighting, photography light meters and smartphone light sensors.
Lux in other illumination units
- 1 lx = 0.001 klxKilolux
- 1 lx = 1000 mlxMillilux
- 1 lx = 0.09290304 fcLux to Foot-candle converter
- 1 lx = 0.0001 phLux to Phot converter
Lux quick reference
| Lux | Foot-candle | Phot | Kilolux |
|---|---|---|---|
| 1 lx | = 0.09290304 fc | = 0.0001 ph | = 0.001 klx |
| 10 lx | = 0.9290304 fc | = 0.001 ph | = 0.01 klx |
| 100 lx | = 9.290304 fc | = 0.01 ph | = 0.1 klx |
| 1000 lx | = 92.90304 fc | = 0.1 ph | = 1 klx |
Where the lux fits
The next smaller illumination unit is the millilux (mlx). 1 lx = 1000 mlx, and 1 mlx = 0.001 lx.
The next larger illumination unit is the foot-candle (fc). 1 lx = 0.09290304 fc, and 1 fc ≈ 10.76391042 lx.
Frequently asked questions
- How many foot-candles are in one lux?
- One lux = 0.09290304 fc (foot-candles).
- How many phots are in one lux?
- One lux = 0.0001 ph (phots).
- How many kilolux are in one lux?
- One lux = 0.001 klx (kilolux).