Online Calculators & Tools




Watts to lux calculator with formulas


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



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

Watts to lux calculation :-

Watts to lux calculation with area in square feet

The illuminance Ev in lux (lx) is equal to 10.76391 times the power P in watts (W), times the luminous efficacy η in lumens per watt (lm/W) divided by the surface area A in square feet (ft2):

Ev(lx) = 10.76391 × P(W) × η(lm/W) / A(ft2)

Watts to lux calculation with area in square meters

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

Ev(lx) = P(W) × η(lm/W) / A(m2)