Lumens, Lux, and Foot-Candles

Light output vs. Light intensity

Lumens is a measurement of light output.  Lux and Foot-candles are a measurement of light intensity.  Lumens, Lux, and Foot candles are closely related, but often confused as to the meaning and how to use the information to make lighting decisions.

Understanding Lumens

Lumens are generally indicated on specifications of lighting fixtures or light sources such as bulbs, tubes, strips, or other products.  Lumens are a measurement of the total light output of a device at the light source.

Understanding LUX and Foot-Candles

Lux (lx) and Foot-Candles (fc) are measurements of light intensity or light density.  Light intensity is measured at a specific location, such as at the desktop, or workbench, or the work surface of tools. 

  • LUX is a measurement of Lumens per square meter. 
  • Foot candles is the imperial equivalent and is a measurement of lumens per square foot.  
  • One LUX (lumen per square meter) is equal to 10.7639 foot-candles (lumens per square foot)