Walk into a well-lit American office and the building code behind it was written in foot-candles — an old unit defined as the light from one candle falling on one square foot. The rest of the world specifies the same lighting in lux, the metric unit of one lumen per square meter. They measure the identical physical thing: how much light actually lands on a surface. The bridge is 0.09290304 — multiply lux by it to get foot-candles — which comes from the fact that a square foot is 0.09290304 square meters. A typical office at 500 lux is about 46 foot-candles, right in the range US lighting standards recommend for desk work.

Enter your reading in the Lux (lx) box and the Foot-candles (fc) result appears alongside the Phot (ph) value, an older metric unit equal to 10,000 lux that still shows up in photography literature. The 500-lux example is worth knowing: it is the standard design target for offices, classrooms, and retail floors. Grow-light hobbyists compare PAR meter readings, photographers balance studio strobes, and facilities managers verify OSHA lighting levels — all of them translating between the lux on their meter and the foot-candles in the American spec sheet. Precision matters here because lighting codes set minimums, and this page keeps four decimal places on the foot-candle readout so compliance math stays exact.

With the pre-filled defaults — Lux (lx) 500 — the Illuminance Converter returns Foot-candles (fc) 46.4515, Phot (ph) 0.050000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.