Illuminance (Lux, lx)

Illuminance, measured in lux (lx), describes how much light falls on a given surface area. It is defined as one lumen per square meter. Unlike luminous flux (total light) or luminous intensity (light in a direction), illuminance focuses on the actual amount of light reaching a surface, such as a desk, floor, or road. This makes illuminance the most practical measure for determining whether a space is adequately lit for specific tasks and for meeting lighting standards in workplaces, schools, or public areas.

Think: Light falling on a surface

Remember 1 Lux = 1 lumen per square metre