๐ก Lumens to Lux Calculator
Assumes an idealized point source radiating light equally in all directions.
Enter a light source's total luminous flux (lumens) and its distance (m) to calculate the illuminance (lux) at that point, based on the inverse-square law (illuminance is inversely proportional to the square of the distance from the source). Assumes an isotropic point source emitting light equally in all directions.
How to use
- Enter the light source's total luminous flux (lumens).
- Enter the distance (m) from the light source.
- The illuminance (lux) at that distance is calculated automatically.
FAQ
What is the inverse-square law?
A physics law stating that the intensity of light from a point source is inversely proportional to the square of the distance from it โ doubling the distance reduces illuminance to one-quarter.
What formula is used?
First, luminous intensity (candela) = total flux (lumens) รท 4ฯ, then illuminance (lux) = luminous intensity (candela) รท distance (m) squared.
Does this exactly match real light fixtures?
This calculation assumes an idealized point source radiating light equally in all directions. Directional fixtures (like spotlights) or those with reflectors and lenses will produce different actual illuminance than this calculation.