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Illumination converter

How much light lands on a surface. 4 units, converted from one table of exact factors.

1 lux in every other illumination unit

Computed by the same engine that runs the converter above, so these can never drift apart from it.

FromEqualsUnit
1 lux0.09290304foot-candle (fc)
1 lux0.0001phot (ph)
1 lux0.001kilolux (klx)

What each unit actually is

Most converters give you a number and stop. Where a figure is exact by definition we say so, and where it is an average or shifts with conditions we say that too — that is usually the thing you needed to know.

UnitSymbolWhat it actually is
luxlxOne lumen per square metre. Office lighting is roughly 500.
foot-candlefcOne lumen per square foot. Still standard in US lighting design.
photphThe CGS unit.
kiloluxklxFull daylight is about 10–25 klx.

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