When replacing a new light fixture, we need to know how bright the original light in order to buy a new one having more-or-less the same brightness. Then, we may encounter this problem – how do we convert lumens to watts? After reading this passage, we can also understand the importance of the conversion, what is lumens, and how it relates to power of light bulbs.
How to use the lumen to watt calculator
If we want to convert between lumen & watt, then we can use the first field. For wattage to lumen, we can use the second one. All we need to do is to enter what you would like to transform, and then select the type of the light source. The corresponding value will appear.
* Note: the result is for reference only. Different brands would have different watts or lumens.
Lumens to Watts Conversion Calculator
Wattages to Lumens Conversion Calculator
What is lumen?
When we buy a light bulb, we may notice its power. You may think that higher the power, brighter the bulb. But in fact, power (wattage) and brightness (lumen) of bulb are not directly related.
Lumens refers to the brightness of a light source. For example, the higher the lumen output of a bulb, the brighter the lights. For instance, a 40W LED having 5200 lm is brighter than 100W incandescent lights having 1000 lm. It is the basic technical parameter to compare the brightness of a light source.
Therefore, lumen of a light is like the horsepower of a sports car. Higher the lumen, higher the output of the lights.
Some may ask where can I find the lumens and watts information of a bulb. In fact, the information would be printed on the package of the lights. For instance, the LED light bulb in the above photo has 10 watts producing 800 lumens. It should be noted that 60W is not the power of bulb. Instead, it means this LED bulb is capable to replace 60 watts incandescent. In this example, the luminous efficiency is just 80 lumens per watt. By looking at different brands, we can find the LED bulbs having higher luminous efficiency up to 100 to 130 lumens per watt.
Watt vs Lumen
The wattage reflects the power consumption of the bulb. If the bulb uses 50J energy per second, its power is 50W. It should be noted that not all of the input energy becomes light output. Take the traditional tungsten bulb as an example. About 95% of the input energy is converted into heat loss, so only about 5% of the energy is converted into light.
Therefore, we need to accurately represent the brightness of the bulb through the conversion of wattage and lumens.
The formula converting lumens to watts is –
Lumen = Wattage of Bulb x Luminous Efficacy
Where luminous efficacy is the energy efficiency of the light source.
For instance, a LED bulb has 10W, and its luminous efficacy is 130 lm/W, so its lumen = 10W x 130lm/W = 1300lm
For instance, a halogen bulb has 10W, but the luminous efficacy is just 20lm/W, the lumen becomes 10W x 10lm/W = 200lm
So, we can see although they have the same wattage, after converting it to lumen, the halogen bulb has the lumen output of 200lm. We will need around 6 to 7 halogen bulbs to replace 1 single LED in order to generate the same brightness.
Watts to Lumens Conversion Chart
To give you a general idea on what does the transformation looks like, let’s take a look at the summary chart of watts to lumens, and vice versa.
| Halogen Wattage | Halogen Lumen | Equivalent LED Wattage |
| 50W | 750 lm | 5.8W |
| 300W | 4,500 lm | 34.6W |
| 500W | 7,500 lm | 57.7W |
| 1,000W | 15,000 lm | 115.4W |
| 1,500W | 22,500 lm | 173.1W |
By looking at the conversion chart, we will instantly know that LED is a more energy-saving light source. It is because to generate the same lumen, we will only need around 1/10 of wattage.
Lumen & Watt FAQ
1. How many lumens is 500 watt bulb?
500 watt halogen is quite common for both indoor & outdoor application. According to our research, the 500W halogen bulb has approx. 5000 to 7500 lumens, depending on the brand and quality of the bulbs.
If you are looking for other type of lights, we can take a look at the table below. The chart summaries the lumens of 500 watt lighting fixtures.
See also: 500W halogen LED replacement guide
| Type of 500 watt light source | Lumens |
| Halogen | 7,500 lm |
| LED | 65,000 lm |
| CFL / fluorescent | 42,500 lm |
| Metal halide | 37,500 lm |
| Mercury vapor | 25,000 lm |
| Incandescent | 5,000 lm |
2. How many lumens in a 60 watt bulb?
For 60 watt LED bulb, then the lumen is minimally 4800lm and maximally 7800lm.
For 60 watt halogen bulb, the lumen is around 900lm.
However, the lumen values would not be the same for different brands.
If you would like to buy the 60 watt bulbs with higher energy efficiency, we can find two information on the package – the lumens and watt. We can calculate the lighting efficiency by using this formula: Lumens ÷ Watts. Higher the better.
3. What is the brightest lumen?
What is the brightest lumen for commercial use? For the sports stadium or sea port, each flood lights will maximally consume 5000 watt energy, which is equivalent to 5000 x 130 = 650,000 lumens. For LedsMaster company, the brightest lumen we can produce is around 2,000,000 lumens (15,000 watt LED flood lights). The generally idea is that, if the area is larger, we will need to have brighter lights (the flood lights with higher lumen output).
For residential use like backyard and parking lot, 130,000 would be the brightest lumen. If the brightness is unnecessarily high, it would cause light pollution.
4. How many lumens is already super bright?
If you want to try the super bright lighting, you can have a LED flood lights having 30,000 to 50,000 lumens in the living room. It means the power is around 250 to 400 watts. The light is so blinding & extremely bright that your neighbor would misunderstand that there is an UFO in your home. By pointing this flood lights to the attacker, you can also blind him with ease.