# Light Quantity: lux or lumens?

If you want to buy a bicycle lamp, it is nice to know how much light will give a lamp. Sometimes this is stated in the number of Lux or Lumen. But what is the difference between Lux and Lumen? And what do they mean those numbers?

When buying a new flashlight or headlamp, it is easy to get confused about the different terms that are used. Below you will be able to read more about 3 of the terms, Lumens, Lux and Watt.

Lumens and light

Lumen is a unit of light, which is also known as Luminous flux

Lumens (LM) are a measurement unit, which tells what the total amount of light emitted from a flashlight or headlamp. You can roughly say that the more Lumens the brighter the light.

But Lumens will only show a part of the picture. Producing and creating a perfect beam pattern does not reveal enough information to show how the light output is created. For this we need to use a lux meter.

Most flashlights and headlamps quickly drop in Lumens and promise a higher Lumen output than they can achieve.

Lux and intensity
Lux is a unit of light measurement where the area is also taken into account. 1 lux equals 1 Lumen/m2, in other words – light intensity in a specific area

Lux is used to measure the amount of light output in a given area – one lux is equal to one lumen per square meter. It enables us to measure the total “amount” of visible light present and the intensity of the illumination on a surface.

We use lux because it is an efficient measurement for determining what we see as the brightness of a beam. If the light output is focused on a small area, we see this as very bright light. If the light output is spread in a wide beam over a greater area, we experience this as a weaker light. This is why we use reflectors machined out of massive aluminum, and high quality optics to control the path of light, creating the desired beam pattern with a minimum loss of light.

Watt is a unit for power consumption

Watt shows how much energy the product consumes, not how much light output (lumens) it provides. That is why you should not look after the amount of watt consumed, when buying any kind of light. It will only tell you how quickly it will drain the battery, and not how much light it produces.

It is also worth to know that 1Watt halogen and 1 Watt LED do not produce the same amount of light. The LED Chip is more efficient and will convert much more energy to light than the halogen bulb.

It is important to keep in mind that the more power consumed the more heat is produced, and heat will always result in a loss of energy.

How much light does it provide?
The amount of light you get depends of your source.

To visualize how much light a product provides, it is essential to understand how much the amount of lumen actually is. On this list we give you common known objects and how much light they light they emit measured in lumen.

The Moon = 1Lumen
The flashlight of your phone = 20lumen
A common lightbulb = 450 lumen
A front light of a car = 1500 lumen

Use these common known objects as a reference to how much light you need. Be aware that many manufactors promise a higher lumen output than the product actually can deliver. It is a good idea to look after the Light Curve on the given product. If it is not available, we recommend you to contact and ask the manufactorer, to be sure that the product suits your needs.