Illumination Converter

Convert between lux, foot-candles, kilolux, millilux and phot.

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Result

Illumination units

Every unit below converts to every other one in the calculator. Values are relative to the base unit, the lux (lx).

Illumination units and their value in luxs
Unit	Symbol	System	Value
Lux	lx	SI	Base unit
Kilolux	klx	SI	= 1000 lx
Millilux	mlx	SI	= 0.001 lx
Foot-candle	fc	US customary	≈ 10.76391042 lx
Phot	ph	CGS	= 10000 lx

Lux quick reference

Lux in other illumination units
Lux	Kilolux	Foot-candle	Phot
1 lx	= 0.001 klx	= 0.09290304 fc	= 0.0001 ph
10 lx	= 0.01 klx	= 0.9290304 fc	= 0.001 ph
100 lx	= 0.1 klx	= 9.290304 fc	= 0.01 ph
1000 lx	= 1 klx	= 92.90304 fc	= 0.1 ph

Among the 5 illumination units on this page, the smallest is the millilux (mlx) and the largest is the phot (ph).

More illumination conversions

About illumination units

Illuminance is the amount of light falling on a surface, per unit area. Its SI unit is the lux (lx), one lumen per square meter. Light meters and lighting design guides measure illuminance; an office is typically around 500 lx and direct sunlight roughly 100,000 lx.

Illuminance is not the brightness of the surface itself; that is luminance, in nits. In the US, lighting is often specified in foot-candles: 1 fc is one lumen per square foot, about 10.7639 lx. The CGS phot is one lumen per square centimeter, exactly 10,000 lx.

Frequently asked questions

How many lux are in a foot-candle?: About 10.7639 lux. One foot-candle is one lumen per square foot, and a square foot is exactly 0.09290304 m², so 1 fc = 1 ÷ 0.09290304 lx.
Can I convert lux to lumens?: Only if you know the area. Lux is lumens per square meter, so lumens = lux × area in m². For example, 500 lx evenly over 2 m² is 1000 lm.
How many kilolux are in one lux?: One lux = 0.001 klx (kilolux).
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).