What is the Difference Between Lux and Lumen?

Lux and lumen are both units of measurement for light, but they serve different purposes and represent different aspects of light emission. Here are the key differences between them:

• Lumen (lm): Lumens measure the total amount of light emitted by a light source, regardless of the distance at which the light source is placed or the surface area it illuminates. In other words, it represents the luminous flux or the intensity of the light source itself. A higher lumen value indicates that the light source produces more light.
• Lux (lx): Lux, on the other hand, measures the amount of light output in a given area. One lux is equal to one lumen per square meter. It tells you how bright a surface will be when illuminated by a light source. Lux takes into account the area over which the light is spread, and it is used to determine the intensity of light on a specific surface.

In summary, lumens measure the total light output of a source, while lux measures the intensity of light on a specific surface. To make a comparison using the examples provided:

• A 1000 lumen light source spread over an area of 1 square meter will illuminate that area with an intensity of 1000 lux.
• The same 1000 lumen light source spread over an area of 10 square meters will illuminate that area with an intensity of 100 lux.

Comparative Table: Lux vs Lumen

Here is a table that shows the difference between lumens and lux:

In summary, lumens measure the total amount of visible light emitted by a source, while lux measures the intensity of light within a specific area or on a surface. Lumens are used to determine the brightness of a light fixture, while lux is used to determine the amount of light that falls on a surface.