How do I convert lux to foot-candles?

1 foot-candle = 10.764 lux. To convert lux to foot-candles, divide by 10.764. For example, 500 lux = 46.5 fc.

What is the relationship between lux and lumens?

lux = lumens / square meters (lux = lm/m²). So to find total lumens needed, multiply the target lux level by the room area in m².

What is the difference between candela and lux?

Candela (cd) measures luminous intensity — how bright a light source is in a given direction. Lux measures illuminance — how much light reaches a surface. For a point source: illuminance (lux) = candela / distance².

💡Light Intensity Converter

lux ↔ foot-candle · lux×area→lm · candela+distance→lux

① Illuminance converter (lux ↔ foot-candle)

Illuminance value

From unit

② Illuminance × Area → Lumens (lm)

Illuminance (lux)

Area (m²)

③ Candela + Distance → Illuminance (lux)

Luminous intensity (cd)

Distance (m)

How to Use the Light Intensity Converter

Three tools in one: ① convert lux to foot-candles, ② calculate total lumens needed for a room, and ③ find the illuminance from a point light source at a given distance.

Unit Overview

lux (lx): SI unit of illuminance. 1 lux = 1 lm/m². International standard for measuring light levels on surfaces.

foot-candle (fc): US unit of illuminance. 1 fc = 10.764 lux. Widely used in North American lighting design and photography.

lumen (lm): Unit of luminous flux — total light output from a source. 1 lm spread over 1 m² = 1 lux.

candela (cd): Unit of luminous intensity — directional brightness of a source. For a point source: lux = cd / distance².

Typical Illuminance Levels

Sunlight outdoors: 100,000 lux / Bright office: 500–1,000 lux / Comfortable reading: 300–500 lux / Corridor: 50–150 lux / Full moon: ~0.1 lux

FAQ

I need 400 lux in a 15 m² room — how many lumens do I need?

400 lux × 15 m² = 6,000 lm. In practice, add ~20–30% for luminaire efficiency and maintenance factors. Use calculator ② above.

What is 50 foot-candles in lux?

50 × 10.764 = 538.2 lux. Enter 50 in calculator ① with foot-candle selected to see all conversions instantly.