Illumination Converter

Convert between illuminance units including lux, kilolux, foot-candles (lm/ft²), phot (lm/cm²), and nox. Used in photography, lighting design, and building standards.

Illumination Converter 5 units

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Common Illumination Conversions

All Illumination Conversions

Browse all unit combinations — each page has a dedicated converter and conversion table.

Nox → Lux Nox → Foot-candles Nox → Kilolux Nox → Phots Lux → Nox Lux → Foot-candles Lux → Kilolux Lux → Phots Foot-candles → Nox Foot-candles → Lux Foot-candles → Kilolux Foot-candles → Phots Kilolux → Nox Kilolux → Lux Kilolux → Foot-candles Kilolux → Phots Phots → Nox Phots → Lux Phots → Foot-candles Phots → Kilolux

📐 How to Use

Choose the illuminance unit your meter or standard uses in the From dropdown and the unit you need in the To dropdown.
Type the reading into the value box and the converted illuminance appears at once, with the pair written out below it.
Use the swap arrows to go from lux to foot-candles or back without changing the dropdowns by hand, then Copy the result.
Click an entry in the Common Illumination Conversions grid to load that pair, or follow an All Illumination Conversions link to a page with its own conversion table.

❓ Frequently Asked Questions

QHow many lux are in 1 foot-candle?

1 foot-candle is 10.7639 lux, the number of square feet in a square meter. Reversed, 1 lux is 0.09290313 foot-candles, so a 500 lux office target is about 46.5 foot-candles under a US lighting standard.

QWhat is 50 foot-candles in lux?

50 foot-candles converts to 538.195 lux. That level is a common office and classroom specification, which is why European and American lighting documents describing the same room appear to quote wildly different numbers.

QCan I convert lumens to lux here?

No, and not anywhere without an area. Lumens measure the total light a source emits, lux measures how much reaches each square meter. Divide lumens by the lit area in square meters to get an average lux, then use this tool.

QWhat are the phot and the nox?

A phot is one lumen per square centimeter, making 1 phot equal to 10,000 lux. A nox is a thousandth of a lux, coined for very dim conditions such as night vision work. Both come from the CGS era and appear in older photometry.

ℹ️ About Illumination Conversion

Illuminance is luminous flux arriving on a surface per unit of area, which is what a light meter held at a desk actually reads. One lux is one lumen spread over a square meter, and a foot-candle is one lumen over a square foot, so a foot-candle is the larger unit by the 10.7639 square feet in a square meter. The quantity most often mistaken for it is luminous flux itself, measured in lumens, which states a lamp's total output rather than what lands on anything, so a lumen rating cannot become lux without an area.

Five illuminance units are covered, all converted through the lux. Results of ten or more are given to four decimal places and smaller ones to six or eight, with trailing zeros removed. Everything is worked out on your own machine while you type.

📏 5 Supported Units

Nox (nox), Lux (lx), Foot-candle (fc), Kilolux (klx), Phot (ph).