IlluminanceConversion Formulas & Examples
Foot-candle → Lux
1 fc = 10.7639 lxExample: 10 fc = 107.6391 lx
Lux → Foot-candle
1 lx = 0.092903 fcExample: 10 lx = 0.92903 fc
Frequently Asked Questions
Q.What is the exact conversion between lux and foot-candles?
One foot-candle (fc) equals 10.76391 lux (since 1 m² ≈ 10.76391 ft²). Conversely, 1 lux equals approximately 0.092903 foot-candles.
Q.What is a phot (ph) in illuminance measurement?
A phot is the CGS unit of illuminance equal to 1 lumen per square centimeter, which equals 10,000 lux (or approximately 929.03 foot-candles).
Q.What is the difference between lumens and lux?
Lumens measure total luminous flux emitted by a light source, while lux measures illuminance—how much of that light falls on each square meter of surface (1 lux = 1 lumen/m²).
Q.What are typical indoor and outdoor lux levels?
Standard office lighting is typically 300–500 lux (≈ 28–46 fc), overcast daylight is around 1,000 lux, and direct midday sunlight reaches 100,000+ lux.