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:
Lumens to lux calculation 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))
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