# Lux to watts calculator

Illuminance in lux (lx) to electric power in watts (W) calculator and how to calculate.

Enter the illuminance in lux, luminous efficacy in lumens per watt, surface area in square feet / meters or spherical radius in feet / meters and press the Calculate button to get the power in watts:

 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

Watts to lux calculator ►

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

## Lux to watts calculation formula

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

So The luminous flux ΦV in lumens (lm) is equal to 0.09290304 times the illuminance Ev in lux (lx) times the surface area A in square feet (ft2).

ΦV(lm) = 0.09290304 × Ev(lx) × A(ft2)

So The power P in watts (W) is equal to the luminous flux ΦV in lumens (lm), divided by the luminous efficacy η in lumens per watt (lm/W).

P(W) = ΦV(lm) / η(lm/W)

So the power P in watts (W) is equal to the 0.09290304 times the illuminance Ev in lux (lx) times the surface area A in square feet (ft2), divided by the luminous efficacy η in lumens per watt (lm/W).

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

So

watts = 0.09290304 × lux × (square feet) / (lumens per watt)

or

W = 0.09290304 × lx × ft2 / (lm/W)

#### Example 1

What is the power consumption with illuminance of 40 lux, luminous efficacy of 15 lumens per watt and surface area of 300 square feet?

P = 0.09290304 × 40 lx × 300 ft2 / 15 lm/W = 74.32 W

#### Example 2

What is the power consumption with illuminance of 60 lux, luminous efficacy of 15 lumens per watt and surface area of 300 square feet?

P = 0.09290304 × 60 lx × 300 ft2 / 15 lm/W = 111.48 W

#### Example 3

What is the power consumption with illuminance of 100 lux, luminous efficacy of 15 lumens per watt and surface area of 300 square feet?

P = 0.09290304 × 100 lx × 300 ft2 / 15 lm/W =185.80 W

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

The luminous flux ΦV in lumens (lm) is equal to the illuminance Ev in lux (lx) times the surface area A in square meters (m2).

ΦV(lm) = Ev(lx) × A(m2)

The power P in watts (W) is equal to the luminous flux ΦV in lumens (lm), divided by the luminous efficacy η in lumens per watt (lm/W):

P(W) = ΦV(lm) / η(lm/W)

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

P(W) = Ev(lx) × A(m2) / η(lm/W)

So

watts = lux × (square meters) / (lumens per watt)

or

W = lx × m2 / (lm/W)

#### Example 1

What is the power consumption with illuminance of 40 lux, luminous efficacy of 16lumens per watt and surface area of 18 square meters?

P = 40 lx × 18 m2 / 16 lm/W = 45W

#### Example 2

What is the power consumption with illuminance of 60 lux, luminous efficacy of 16 lumens per watt and surface area of 18 square meters?

P = 60 lx × 18 m2 / 16 lm/W = 67.5W

#### Example 3

What is the power consumption with illuminance of 100 lux, luminous efficacy of 16 lumens per watt and surface area of 18 square meters?

P = 100 lx × 18 m2 / 16 lm/W = 112.5W

Lux to watts calculation ►

## Features of Lux to watts Calculator

Our Lux to watts Calculator allows the users to Calculate Lux to watts . Some of the prominent features of this utility are explained below.

#### No Registration

You don’t need to go through any registration process to use the Lux to watts Calculator. Using this utility, users to Calculate Lux to watts as many times as you want for free.

#### Fast conversion

This Lux to watts Calculator offers users the fastest Calculate. Once the user enters the  Lux to watts values ​​in the input field and clicks the Calculate button, the utility will start the conversion process and return the results immediately.

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The online Lux to watts converter perfectly works on all operating systems. Whether you have a Mac, iOS, Android, Windows, or Linux device, you can easily use this online Tool without facing any hassle.

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You don't need to go through any registration process to use this Lux to watts Calculator. You can use this utility for free and do unlimited Lux to watts Calculate without any limitations.