Watts to Lux Calculator

Watts To Lux Calculator

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

Watts to Lux calculator

It is used to convert the electric power in watt (W) to illuminance in lux (lx). It has four text fields and options of executing the conversion. The watts to lux calculator also has two controls, ‘Calculate’ and ‘Reset’ buttons which operate independently performing different functions of the calculator. The first step is to enter the value of power in watts.

Select the light source in the options provided by the calculator. If you do not find the particular appliance, you will manually enter the value of luminous efficacy in lumens per watt. The next step is to enter the surface are or the spherical radius and then click the ‘Calculate’ button to initiate the process of conversion. Your results are displayed within a single click in the bottom platform of the calculator below the two controls.

For example;

Determine the illuminance in lux of a LED lamp having 240 watts and a surface area of 1000 square feet.

Solution;
If you are using the calculator, you will first enter 240 as the power in watts. Select LED lamp as the source of light and then enter 1000 as the surface area. The spherical radius will be calculated automatically as; 8.9206205808 feet.

You can also choose to display the values in meters. The illuminance result in lux will be; 155.000304 (lx).

Formula used in calculating watts to lux

Squared feet
Ev (lx) = 10.76391 x P (W) x η (lm / W) / A (ft2), which means that the illuminance in lux is calculated by 10.76391 multiplied by the power in watts by the luminous efficacy in lumens. The result is then divided by the surface area in square feet.

Squared meters
Ev (lx) = P (W) x η (lm / W) / A (m), where the illuminance in lux is calculated by the power in watts multiplied by the luminous efficacy in lumens per watt. The result is then divided by the surface area in square meters.

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