Illuminance Converter

Use this tool to convert between different units of illuminance, such as Lux, Foot-candle, Phot, and more.

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Common Illuminance Conversions

lux to foot-candle lx → fc
phot to lux ph → lx
foot-candle to lux fc → lx
lux to phot lx → ph

What is Illuminance Conversion?

Illuminance conversion is the process of converting measurements of luminous flux incident on a surface from one unit to another. Our illuminance converter tool helps switch between SI units (lux) and CGS units (foot-candles, phot) used in lighting design and photography.

Common units include lux (lx), foot-candles (fc), and phot (ph). These conversions are essential for architectural lighting design, photography exposure calculations, horticulture lighting, and workplace safety compliance.

Simply enter your value in the "From" field, select the original unit, choose your target unit in the "To" field, and the converter will instantly display the converted result along with the conversion formula.

Illuminance Conversion Examples

Photography Example

Studio lighting measurements:

  • 1000 fc = 10,764 lux
  • 100 lux = 9.29 fc
  • Bright sunlight ≈ 10,000 fc

Workplace Example

Office lighting requirements:

  • 500 lux ≈ 46 fc
  • Office standard: 500 lx
  • Drafting areas: 750 lx

Natural Light Example

Daylight illuminance levels:

  • Full daylight: 1000-25,000 lux
  • Overcast day: 1000 lux
  • Full moon: 0.1 lux

Frequently Asked Questions

How many lux in a foot-candle?

One foot-candle (fc) equals exactly 10.7639 lux (lx). This conversion is essential for architectural and lighting design projects involving both metric and imperial specifications.

How do I convert lux to foot-candles?

To convert lux to foot-candles, divide by 10.7639. For example, 500 lux ÷ 10.7639 ≈ 46.45 fc. This conversion is commonly used in US construction projects.

How many lux in a phot?

One phot (ph) equals exactly 10,000 lux. The phot is a CGS unit rarely used today but sometimes found in older scientific literature and some specialized applications.

What is the recommended office illuminance?

Typical office illuminance recommendations: General offices: 300-500 lux, Computer workstations: 500 lux, Meeting rooms: 300-500 lux, Drafting areas: 750 lux. Adequate lighting reduces eye strain.

What is the formula for fc to lux conversion?

To convert foot-candles to lux, multiply by 10.7639. For example, 100 fc × 10.7639 = 1076.39 lux. This conversion bridges imperial lighting units with SI standards.