Photometry Tools
Lumens to Lux Calculator
Convert total light flux output in lumens (lm) to surface illuminance density in lux (lx).
Calculation Input
Illuminance Density
0.00 lx
Equivalent Footcandles (fc)
0.00 fc
Illuminance Class Target
Normal Office Desk
Understanding Luminous Flux vs Illuminance
Lumens ($lm$) measures the total overall light emitted by a lamp, while lux ($lx$) measures how much of that light lands on a specific surface area. The mathematical formula dividing overall light output by total area is:
$$E_{lx} = \frac{\Phi_{lm}}{A_{m^2}}$$
Where $A$ is surface area in square meters. If the area is measured in square feet, it must be multiplied by $0.092903$ to convert to square meters first.