Illuminance Converter Tool
Convert between lux, foot-candles, phots, and other illuminance units instantly
Conversion Result:
100 lux = 9.2903 foot-candles
About Illuminance Conversion
Illuminance is a measure of how much luminous flux is spread over a given area. It’s an important concept in lighting design, photography, and various scientific applications. Our free illuminance converter tool helps you quickly convert between different units like lux, foot-candles, phots, and nox.
Whether you’re a photographer adjusting camera settings, an architect designing lighting systems, or a student studying photometry, this tool provides accurate conversions instantly. The converter is mobile-friendly and works seamlessly across all devices, ensuring you get precise results wherever you are.
Common Illuminance Units:
- Lux (lx): The SI unit of illuminance, equal to one lumen per square meter
- Foot-candle (fc): Equal to one lumen per square foot (approximately 10.764 lux)
- Phot (ph): A CGS unit equal to 10,000 lux
- Nox (nx): Equal to 0.001 lux, used for very low light levels
Frequently Asked Questions
What is illuminance and how is it different from luminance?
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Illuminance measures the amount of light falling on a surface (incident light), while luminance measures the light emitted or reflected from a surface. Illuminance is measured in lux, while luminance is measured in candela per square meter.
How many lux is direct sunlight?
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Direct sunlight typically provides between 32,000 and 100,000 lux, depending on atmospheric conditions, time of day, and geographical location. Overcast daylight ranges from 1,000 to 2,000 lux.
What is the conversion factor between lux and foot-candles?
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One foot-candle equals approximately 10.764 lux. Conversely, one lux equals approximately 0.0929 foot-candles. This conversion factor comes from the relationship between square meters and square feet (1 m² = 10.7639 ft²).
When would I use a phot instead of lux?
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The phot is a CGS unit of illuminance equal to 10,000 lux. It’s rarely used today but might appear in older scientific literature. For most modern applications, lux is the preferred unit.
What illuminance level is recommended for office work?
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For general office work, recommended illuminance levels range from 300 to 500 lux. For detailed technical work, 750 to 1,000 lux may be required. These recommendations vary by country and specific task requirements.