Lux vs Lumens on Bike Lights

Most bicyclists have heard of lumens, especially when it comes time to purchase a bike light. Many bike lights are advertised by the number of lumens that they have, as though this is an indication of the light’s quality.  It is not necessarily so. This term applies to a measure of the total amount of light that the light source emits. The more lumen value a bike has, the greater its light output.

Lux, on the other hand,  gives the rider the necessary information about how adequate that light is, and informs the rider about whether or not the light will meet their needs.

Simply put, the two expressions measure either the power of a light beam or its volume.The higher the value of lumens a bike light has, the more light it produces.  However, without the ability to harness that light and direct it to a specific area, the brightness does little good at all when cycling.

Lux tells the rider what they need to know about the brightness of a point, such as a trail marking, in a specific area, or how widespread the light is and how it might effect oncoming cars, for instance. . Lux values increase when light focuses on one site.

Lux vs Lumens on Bike Lights

How many lumens are in a bike light?

A typical question to ask when purchasing a bike light is, “How many lumens does this light have?” Light manufacturers have picked up on consumer interest in this number and usually place it prominently next to the title in their online advertisements.The answer to how many lumens are in a light, however,  is not that simple. Different parameters must be taken into consideration before a true determination can be made, and this includes figuring the lux into the equation.

Generally speaking, a single lux is equal to a single lumen per square meter. However, when you consider the angle of light radiation and the distance that the light travels, the answer can change.The various light modes differ from one another when testing the modes for the lumen and lux.  However, it can be easy to figure out which one of the lighting calculators online can assist with the conversion.

Lux vs lumens on bike lights – which is better?

Most bike light manufacturers will advertise the number of lumens associated with their lights, meaning that they present them with high lumen numbers to convey that the lights are bright. The higher the number, the brighter the light. However, there is much more to consider than just this number, because the  number of lumens neglects to consider how the light is distributed, which can make a huge difference when riding, particularly after dark.   A good thing to remember is that a high lumen number designates a quantity, but it doesn’t say anything about the light’s quality, and how effective the beam is.

Bike riders find it necessary to feel confident about the light they use so that they can be seen or see better without blinding other road occupants.  This is where the lux comes in.  Lux numbers determine the quality of light when it is focused on a specific area. For instance, a mountain bike rider might need a wider beam of light to illuminate the entire width of a path, while a rider on a paved bike path alongside a road might need a narrower beam.This width is determined by the lux rating.

If you need the most accurate way to measure the output of a light, then the lux number is the way to go, because it measures the light value of a surface a precise distance away.  It doesn’t only measure the brightness, which is the case with the lumens rating.  More and more light manufacturers are switching over to the promotion of lux rather than lumen ratings on their packaging and in ads wit the message that the way a light illuminates the area in front of the bike is a lot more important than how bright the light is itself.  Lux is what really matters.


When shopping for bike lights, it is not uncommon for a consumer to confuse the meanings of lux and lumens.  Where sales are concerned, businesses often promote the larger, more impressive number,the lumens. Therefore, a consumer is much more likely to automatically reach for a bike light that is advertised as having 6,000 lumens rather than 2,200 lux.  After examination of the light, however, it could be sound that the 2,200 lux light was the better choice, because it was needed for a bike route that normally faced a lot of oncoming traffic.

In this case, the thing with which to concern oneself would be whether or not the light flashed directly into the faces of oncoming drivers and temporarily blinded them.  The lux number in this instance would help the rider figure out the intensity of the beam and where it would be directed.   Lux vs lumens on bike lights can be a huge safety factor.

It is important to remember that while lumens measure the light’s output, a higher number doesn’t necessarily mean that this particular light is the  most functional choice.  It would serve the public and bike safety tremendously if the manufacturers of bike lights would refocus their attention to the combination and the roles that each play individually to help cyclists be safer on the road.  Rather than publishing the lumen numbers because they are higher than lux numbers, they should either start to publish both numbers or just the lux.  By failing to do this, they open the door to much biker confusion and misdirection.

Lux vs lumens on bike lights can mean the difference between a safe bike journey and a tragic accident caused by the biker using the wrong light type for the particular trail or path they have chosen.  Lux provides a way to integrate more safely into riding with traffic.


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