Illuminance Converter
Lux (lx)
Definition: The lux (symbol: lx) is the SI derived unit of illuminance and luminous emittance. It measures luminous flux per unit area and is equal to one lumen per square meter.
History/origin: The unit comes from the Latin word "lux," meaning light. It was introduced in 1889 and formally adopted into the International System of Units (SI) to provide a standard measure for human-perceived light intensity.
Current use: Lux is the universal standard used to measure indoor and outdoor lighting levels, workplace safety lighting standards, and environmental lighting for plants and animals.
Foot-candle (fc)
Definition: A foot-candle (symbol: fc, lm/ft², or ft-c) is a non-SI unit of illuminance used primarily in the United States customary system. It is defined as one lumen per square foot.
History/origin: Historically, it was defined as the illuminance produced on a surface by a standard "spermace candle" (a candle made from whale oil) at a distance of exactly one foot. It was the common unit before metric standardization.
Current use: Foot-candles are still widely used in the United States and the UK by architects, cinematographers, photographers, and stage lighting designers to set up optimal lighting environments.
Lux (lx) to Foot-candle (fc) Conversion Table
| Lux (lx) [lx] | Foot-candle (fc) [fc] |
|---|---|
| 0.01 lx | 0.00092903 fc |
| 0.1 lx | 0.0092903 fc |
| 1 lx | 0.09290304 fc |
| 2 lx | 0.18580608 fc |
| 3 lx | 0.27870912 fc |
| 5 lx | 0.4645152 fc |
| 10 lx | 0.9290304 fc |
| 20 lx | 1.8580608 fc |
| 50 lx | 4.64515201 fc |
| 100 lx | 9.29030401 fc |
| 1000 lx | 92.90304014 fc |
How to Convert Lux (lx) to Foot-candle (fc)
1 lx = 0.09290304 fc
1 fc = 10.7639104 lx
Example: convert 15 lx to fc:
15 lx = 15 × 0.09290304 fc = 1.3935456 fc
Did You Know?
- Did you know? Direct, bright sunlight can measure over 100,000 lux, while a typical well-lit office is around 500 lux. On a clear night, the full moon provides only about 0.1 lux of illumination!
- The term "Foot-candle" is completely literal! Historically, it was defined as the exact amount of light cast by a single standard candle onto a surface exactly one foot away.