Units of Light

3 units of light in the database, across 2 measurement systems, each with its exact or best-known SI value.

UnitSymbolQuantityValue in SI
CandelacdLuminous intensityBase unit; Kcd = 683 lm/W at 540 × 10¹² Hz exactly
LumenlmLuminous flux1 lm = 1 cd·sr
LuxlxIlluminance1 lx = 1 lm/m²