Luminance vs Illuminance

This luminance converter works with the light a surface emits or reflects — luminance — measured in candelas per square meter. Illuminance, by contrast, is the light arriving at a surface (lux). The two are linked by a surface's reflectivity but are distinct quantities.

The Unit Ladder

One footlambert equals 3.426 cd/m², one cd/ft² equals 10.764 cd/m², and one stilb equals 10,000 cd/m². Every conversion here is an exact factor multiplication from the base unit — no estimation involved.

Reading Spec Sheets

Phone and TV brightness is quoted in nits; projectors and film may quote footlamberts or lumens-per-area. Converting to one common unit lets you compare displays fairly regardless of the manufacturer's choice of units.