Lumens

Lumens measure the total amount of visible light emitted by a light source, be it electric, natural or artificial. Lumens measure the brightness of a light source and are used to compare different levels of illumination. The higher the number of lumens, the brighter the light source. For example, an LED bulb that produces 1000 lumens is much brighter than a 25 watt incandescent bulb producing 400 lumens.