What is the unit for luminous flux?

Luminous flux is measured in lumens (lm), which quantifies the total amount of visible light emitted by a source per unit time. This unit takes into account how human vision perceives brightness and is essential for understanding lighting applications. While watts measure power and relate to energy consumption, lumens directly address visual output, making it the appropriate unit for luminous flux.

Lux, on the other hand, represents illuminance, which describes how much luminous flux is spread over a given area, while candela measures the intensity of light emitted in a particular direction. These definitions clarify that lumens are the correct unit for assessing the total light output of a source.