Electricity is used as one of the main sources for producing light. We use different rating bulbs for lightning. And we know that how much the watt rating of a bulb is. The more the watt the more the brightness will the bulb produce. In this article, we will study a the term “Lumen” and will discuss the conversion of Lumens to watts.

**Should I use Lumen or Watt to describe a lamp?**

We can define the lumen in a very simple way** “the measurement of visible light from a light source such as bulb or Lamp etc.”** The lumen is denoted by lm. The more brighter the light the higher the value of lumen.

Most people describe light bulbs and lamps using watt. This is not the true way as the watt is the electrical energy that the lamp consume. lighting lamps output is not in watt but it is in lumen. This is why it is important when purchasing a new lighting lamp or spot light to check the lumen of the lamp. Some poor quality lamps consume high power in watt and don’t produce much brightness.

## lumens to watts** formula**

We can measure the efficiency of lighting products such as bulbs, lamps, etc. from the lumens to watts relationship. Therefore, the efficiency of a bulb or lamp will be the amount of total output light (in Lumens) divided by the power used (in watts). So using this relation we can decide and measure the efficiency of lighting product. Let’s take an **example.**

**Assume there are two lighting products “A “and “B”. Light A offers a light output of 4000 Lumens for 20 Watts of power. And Light B offers Light output for 5000lumens for 40 watts of power.**

Now according to lumens to watts relation we can determine the efficiency of each product.

- For Product A, Lumen per watt relation= 4000 lm / 20 watt
- The efficiency of Product A =200 Lm/ W

- For Product B, Lumen per watt relation= 5000 lm / 40 watt
- The efficiency of Product A =125 Lm/ W

So from the formula , we decide that product “A” is the best choice to use not product “B”.

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