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Lumens to lux conversion calculator with formulas

Luminous flux in lumens (lm) to illuminance in lux (lx) calculator and how to calculate.

Enter the luminous flux in lumens, select area unit type, enter radius in meters for spherical light source or surface area

in square meters for any light source and press the Calculate button to get the illuminance in lux:



Enter luminous flux in lumens: lm
Select area unit type:  
 
Enter spherical radius:
 
Or enter surface area:
 
   
Illuminance result in lux: lx



Lumens to lux conversion formula

Calculation with area in square feet

The illuminance Ev in lux (lx) is equal to 10.76391 times the luminous flux ΦV in lumens (lm) divided by the surface area A in square feet (ft2):

Ev(lx) = 10.76391 × ΦV(lm) / A(ft2)

 

The illuminance Ev in lux (lx) is equal to 10.76391 times the luminous flux ΦV in lumens (lm) divided by 4 times pi times the squared sphere radius r in feet (ft):

Ev(lx) = 10.76391 × ΦV(lm) / (4⋅π⋅r(ft)2)

 

Calculation with area in square meters

The illuminance Ev in lux (lx) is equal to the luminous flux ΦV in lumens (lm) divided by the surface area A in square meters (m2):

Ev(lx) = ΦV(lm) / A(m2)

 

The illuminance Ev in lux (lx) is equal to the luminous flux ΦV in lumens (lm) divided by 4 times pi times the squared sphere radius r in meters (m):

Ev(lx) = ΦV(lm) / (4⋅π⋅r 2(m2))