# Online Lux to watts Calculator

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# Lux to watts calculator

#### Lux to watts

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.

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).

#### Lux to watts calculation formula

Lux to watts calculation with area in square feet

The power P in watts (W) is equal to the 0.09290304 times the illuminance *E*_{v} in lux (lx) times the surface area *A* in square feet (ft^{2}), divided by the luminous
efficacy * η* in lumens per watt (lm/W):

*P*_{(W)} = 0.09290304* *×* E*_{v(lx)}* *×* A*_{(ft}2_{)} /* η*_{(lm/W)}

#### Lux to watts calculation with area in square meters

The power P in watts (W) is equal to the illuminance *E*_{v} in lux (lx) times the surface area *A* in square meters (m^{2}), divided by the luminous
efficacy * η* in lumens per watt (lm/W):

*P*_{(W)} = *E*_{v(lx)}* *×* A*_{(m}2_{)} /* η*_{(lm/W)}