Photometry Tools
Lux to Candela Calculator
Convert illuminance in lux (lx) to directional intensity in candelas (cd) over a specified distance.
Calculation Input
Luminous Intensity
0.00 cd
3.5m
Intensity Level Rating
Normal Spotlight
Equivalent Footcandles
0.00 fc
Inverse-Square Law for Luminous Intensity
To find the directional luminous intensity of a light source in candelas ($cd$) from illuminance measured in lux ($lx$), we multiply lux by the square of the distance. Candelas remains independent of distance:
$$I_{cd} = E_{lx} \times d^2$$
Where $d$ is distance in meters. If $d$ is in feet, it must be multiplied by $0.3048$ to convert to meters first.