# Lux to watts calculator

## Lux to watts calculator

We are offering the best online calculators to find Illuminance in lux (lx) to electric power in watts (W) to calculate.

You can simply enter the value of illuminance in lux, luminous efficacy in lumens per watt, with the surface area in square feet / meters or the spherical radius in feet / meters and hit the = button to find the value of power in watts.

[Lightning_l_Lux_to_watts_calculator]

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

## Formula for Lux to watts calculation

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

The power P measured in watts (W) is apparently equal to the 0.09290304 times the value of illuminance Ev measured in lux (lx) multiplied by the surface area A in square feet (ft2), and lastly divided by the luminous efficacy η measured in lumens per watt (lm/W).

P(W) = 0.09290304 × Ev(lx) × A(ft2) / η(lm/W)

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

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

P(W) = Ev(lx) × A(m2) / η(lm/W)