Light Intensity Conversion Calculator

Unit

Formula for Light Intensity

The formula for light intensity (III) based on the inverse square law is:

I = \frac{P}{4 \pi r^2}

Where:

  • I = Light intensity (in lumens per square meter lm/m² or lux)
  • P = Power of the light source (in lumens lm)
  • r = Distance from the light source (in meters m)

Conversion Table

From UnitTo UnitConversion Factor
1 lux1 lumen/m² 1 \text{lux} = 1 \text{lumen/m}^2
1 lumen/m²1 lux 1 \text{lumen/m}^2 = 1 \text{lux}
1 lux0.092903 foot-candle 1 \text{lux} = 0.092903 \text{foot-candle}
1 foot-candle10.764 lux 1 \text{foot-candle} = 10.764 \text{lux}
1 phot10,000 lux 1 \text{phot} = 1 \times 10^{4} \text{lux}
1 lux0.0001 phot 1 \text{lux} = 1 \times 10^{-4} \text{phot}
1 nit1 candela/m² 1 \text{nit} = 1 \text{candela/m}^2
1 candela/m²1 nit 1 \text{candela/m}^2 = 1 \text{nit}

Examples of Light Intensity Conversion

Convert 100 \text{ lux} to \text{foot-candle} :
100 \text{lux} \times 0.092903 \text{foot-candle/lux} = 9.2903 \text{foot-candle}
Convert 20 \text{ foot-candle} to \text{lux} :
20 \text{foot-candle} \times 10.764 \text{lux/foot-candle} = 215.28 \text{lux}
Convert 1 \text{ phot} to \text{lux} :
1 \text{phot} \times 1 \times 10^{4} \text{lux/phot} = 10,000 \text{lux}
Convert 50 \text{ lux} to \text{phot} :
50 \text{lux} \times 1 \times 10^{-4} \text{phot/lux} = 0.005 \text{phot}