## Lux To Watts Conversion Calculator

 Enter illuminance in lux: lx Select light source: -- select light source -- Tungsten incandescent light bulb Halogen lamp Fluorescent lamp LED lamp Metal halide lamp High pressure sodium vapor lamp Low pressure sodium vapor lamp Mercury vapor lamp Or enter luminous efficacy in lumens per watt: lm/W Enter surface area: ft² m² Or enter spherical radius: ft m Power  result in watts: W

### Lux to watts calculator

It is a conversion calculator used to convert the illuminance in lux (lx) to the electric power in watts (W). It has four text fields and two controls that perform different functions of the calculator. The ‘Calculate’ button is used to execute the conversions from lux to watts while the ‘Reset’ button is used to erase all data of the previous calculations from the text fields.

The initial step is to enter the value of illuminance in lux. Select the light source in the options provided by the calculator. You can also fill in the luminous efficacy in lumens per watt in the next text field. Afterwards, enter the surface area or the spherical radius and then click the ‘Calculate’ button. The power result in watts will be displayed in the bottom platform below the two controls.

#### For example;

Determine the power consumption if the illuminance in lux is 450 (lx) with a luminous efficacy of 17 lumens per watt and a surface area of 100 square feet.

##### Solution;
When using the calculator, you will first enter 450 in the first text field, and then 17 as the luminous efficacy in lumens per watt. Proceed to the next text field and enter 100 as the surface area and then click the ‘Calculate’ button.

The spherical radius will be calculated automatically as; 2.8209479177 ft and the power result in watts as; 245.91981176 watts (W).

#### Formula of calculating lux to watts

###### Square feet
P (W) = 0.09290304 x Ev (lx) x A (ft2) / η (lm / W). It means that the power in watts is calculated by multiplying 0.09290304 by the illuminance in lux, and the result is divided by the luminous efficacy in lumens per watt.

###### Square meters
P (W) = Ev (lx) x A (m2) / η (lm / W). It means that the power in watts is calculated by multiplying the illuminance in lux by the surface area in square meters. The result is then divided by the luminous efficacy in lumens per watt.