How Do You Compare LED Light Output to Other Sources?

The most common measurement of light output is the lumen, a unit of light flow or luminous flux. The lumen rating of a lamp is a measure of the total light output of the lamp. Most light sources are labeled with an output rating in lumens. Lumens measure how much light actually falls on a surface.

The unit of measure commonly used to describe LED intensity is the millicandela (mcd). 1000 millicandela equals 1 candela. The candela is a unit of luminous intensity. One candela is defined as the luminous intensity of 1/600,000 square meter of projected area of a blackbody radiator operating at the temperature of solidification of platinum under pressure of 101,325 Newtons per square meter. This simply means that candelas measures how much light is produced as measured at the light source.

How do you convert lumens to mcd? There is not an exact conversion since they are different types of measurements but here is a rough conversion: If you multiply the number of lumens by 80 you can get the equivalent millicandelas (mcd).

A 15 watt fluorescent tube has an output of 870 lumens. It would take approximately 70,000 mcd to equal the same light output. White LEDs have a light output of between 2,000 and 10,000 mcd, depending on their quality and the angle of spread of their beam. The narrower the beam, the higher the mcd rating.