# Lumens to Watts Calculator

## Lumens To Watts Conversion Calculator

 Enter luminous flux in lumens: lm Enter 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 Power result in watts: W

### Lumens to watts calculator

It is a conversion calculator that is used to convert the luminous flux in lumens (lm) to the electric power in watts (W). It delivers accurate results based on the values entered in the text fields which makes it an effective calculator in performing the conversions. It has two controls, the ‘Calculate’ and ‘Reset’ buttons which perform different functions of the calculator.

The initial step is to enter the value of luminous flux in lumens. Afterwards, you can select the light source or enter the luminous efficacy in lumens per watt. Confirm that you have entered the appropriate values in the required text field and then click on the ‘Calculate’ button to execute the conversion. If you want to perform new conversions, the ‘Reset’ button will be useful in erasing all data of the previous calculations from the text field. The power result in watts will be displayed in the bottom platform of the calculator below the two controls.

#### For example;

If a fluorescent lamp has 5000 luminous flux in lumens, calculate the power in watts.

##### Solution;
The first step is to enter 5000 as the value of the luminous flux in lumens and select fluorescent lamp as the light source. The luminous efficacy in lumens per watts is automatically determined by the calculator as it is displayed in the text field.

Click the ‘Calculate’ button to perform the calculation. The power result in watts will be displayed as;

= 83.333333333 watts (W).

This calculator uses a particular formula in executing the conversions.

#### Formula of calculating Lumens to watts

P (W) = Фv (lm) / η (lm/W), which means that the power in watts is calculated by dividing the luminous flux in lumens by the luminous efficacy in lumens per watt. It gives accurate results within a single click according to the input.