What is the Difference between Lumens and Lux

Lumens (symbol: lm) is the derived unit of luminous flux, a measure of the total quantity of visible light emitted by a light source.

Lux, on the other hand, is the measurement of actual light available at a certain distance from the light source. A lux equals one lumen incident per square meter of illuminated surface area. They're measuring the same thing, just using different measurement units.

To put this very simply, lux has the variable of distance from the fitting, whereas the lumen rating is measured at the fitting, and is a fixed value to the light source