Illuminance Converter
Convert between 7 units of illuminance — lux, millilux, kilolux, footcandle, phot, lm/m², and lm/ft².
About the Illuminance Converter
Illuminance measures the amount of luminous flux (visible light) falling on a unit area of surface — essentially how brightly a surface is lit. The SI unit is the lux (lx), defined as one lumen per square metre. The footcandle (fc) is still used in US lighting design and photography. Proper illuminance levels are specified by standards for workplaces, roads, sports facilities, and emergency lighting to ensure safety and productivity.
- ›Direct sunlight provides about 100,000 lux; an overcast sky gives 1,000–10,000 lux
- ›Office lighting standards recommend 300–500 lux at desk level
- ›A full moon provides only about 0.25 lux — making reading difficult outdoors at night
- ›One footcandle = 10.764 lux (the footcandle measures lumens per square foot)
Frequently Asked Questions
What units does the Illuminance Converter support?
The Illuminance Converter supports multiple units with instant conversion. Convert between 7 units of illuminance — lux, millilux, kilolux, footcandle, phot, lm/m², and lm/ft². All results use SI-validated constants accurate to 8 significant figures.
Is this Illuminance Converter free?
Yes — completely free. No registration, no limits. Works on all devices including mobile.
How accurate is this converter?
Accurate to 8 significant figures using precise mathematical constants validated against international SI standards (NIST and ISO 80000).