Convert an illuminance reading from footcandles to lux.
How to Use the Footcandles to Lux Calculator
Type a footcandle reading into the single input field — the Lux card below it updates immediately.
Footcandles and lux both measure illuminance — light falling on a surface — just against different-sized reference areas. A footcandle is one lumen per square foot; a lux is one lumen per square meter. Since a square meter is the bigger area, one lux represents less light per unit area than one footcandle, and the conversion factor between the two is exactly that area ratio.
lux = footcandles × 10.76410.764 is how many square feet fit inside a square meter — a meter runs about 3.28 feet, and 3.28² works out to 10.764. There's no separate physics here beyond that area conversion; footcandles and lux describe the exact same illuminance, just counted against differently sized squares.
A well-lit office desk is often specified around 50 footcandles, about 538 lux, while a dim hallway might call for closer to 5 footcandles, roughly 54 lux. The unit changes; the light on the desk doesn't.
Footcandles still show up constantly in US lighting specs, building codes, and photography light meters — camera and cinematography meters were built around footcandles long before lux-based meters became standard, which is part of why the unit persists in film workflows even outside the US. Lux dominates almost everywhere else, since most of the world standardized on metric units for area and length decades ago.