Photometry Tools
Candela to Lux Calculator
Convert directional luminous intensity in candelas (cd) to illuminance density in lux (lx) over a specified distance.
Calculation Input
Illuminance Result
0.00 lx
3.5m
Target Area Illumination Level
Normal Office Lighting
Equivalent Footcandles
0.00 fc
The Inverse-Square Law of Light
Illuminance measures how much light hits a given surface area. Because light spreads out as it travels from a central point source, the surface illuminance drops in inverse proportion to the square of the distance:
$$E_{lx} = \frac{I_{cd}}{d^2}$$
Where $d$ is distance in meters. If $d$ is in feet, it must be multiplied by $0.3048$ to convert to meters first.