Lux to watts calculator

Illuminance in lux (lx) to electric power in watts (W) calculator and how to calculate.

Enter the illuminance in lux, luminous efficacy in lumens per watt, surface area in square feet / meters or spherical radius in feet / meters and press the Calculate button to get the power in watts:

Enter illuminance in lux:  
lx
Select light source:
Or enter luminous efficacy in lumens per watt:
lm/W
Enter surface area:  
Or enter spherical radius:  
   
 
   
Power  result in watts:  
W

Watts to lux calculator ►

* the predefined luminous efficacy values are typical / average values.

Lux to watts calculation formula

Lux to watts calculation with area in square feet

The power P in watts (W) is equal to the 0.09290304 times the illuminance Ev in lux (lx) times the surface area A in square feet (ft2), divided by the luminous efficacy η in lumens per watt (lm/W):

P(W) = 0.09290304 × Ev(lx) × A(ft2) / η(lm/W)

Lux to watts calculation with area in square meters

The power P in watts (W) is equal to the illuminance Ev in lux (lx) times the surface area A in square meters (m2), divided by the luminous efficacy η in lumens per watt (lm/W):

P(W) = Ev(lx) × A(m2) / η(lm/W)

 

 

Lux to watts calculation ►

 

See also

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