Foot-Candle to Lux Converter (fc to lx

Foot-Candles (fc), Lux (lx), Area Luminous Flux & IESNA Metrology

Illuminance is the density of luminous flux incident on a surface:

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• Universal Illuminance Conversion Formulas (Imperial & SI)**:

1 Foot-Candle (fc) = 1 Lumen/ft^2 = (1) / ((0.3048)^2) Lux = 10.7639104 Lux (lx)

1 Lux (lx) = 1 Lumen/m^2 = 0.09290304 Foot-Candles (fc)

1 Phot (ph) = 1 Lumen/cm^2 = 10,000 Lux ≈ 929.03 Foot-Candles

1 Nox (nx) = 10^-3 Lux = 0.001 lx ≈ 9.29 × 10^-5 fc

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• Total Room Luminous Flux Formula**:

Φ_total = E_lux × A_m^2 = E_fc × A_ft^2 (Total Lumens required)

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• Standard IESNA Illuminance Recommendations**:

• Full Moon Night: 0.02 fc = 0.215 Lux Night navigation

• Outdoor Parking Lot: 2.0 fc = 21.5 Lux Public safety minimum

• Corridor / Restroom: 10.0 fc = 107.6 Lux Circulation paths

• Commercial Office Desk: 50.0 fc = 538.2 Lux Visual reading/typing comfort

• Surgical Operating Table: 10,000.0 fc = 107,639 Lux Precision clinical luminaire

How to Use This Calculator

Enter your Illuminance Magnitude (e.g. 50 in E), From Illuminance Unit — choose from Foot-Candles (fc = lm/ft² - US Lighting Standard), Lux (lx = lm/m² - SI Base Standard), Kilolux (klx = 1,000 lx), To Illuminance Unit — choose from Lux (lx), Foot-Candles (fc), Kilolux (klx), Illuminated Room Area (m²) (e.g. 20.0 in m²), and Architectural & IESNA Lighting Benchmark — choose from Custom Illuminance, Clear Full Moon Night (0.02 fc) → 0.215 Lux, Commercial Parking Lot Night (2.0 fc) → 21.53 Lux. Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Base standard: SI Lux (lx = lm/m²)

Total Lumens for area: Lumens = Lux * Area (m²)

Worked Example

An architectural lighting engineer reading an American building blueprint specifying 50 foot-candles on classroom desks multiplies by 10.764 to specify 538 Lux luminaires for an international construction contractor.

Understanding Your Result

Unit conversion precision: round to the same number of significant figures as your original measurement. Converting 6 feet to meters gives 1.8288 m — but if your measurement was approximate (±1 inch), expressing more than 2 decimal places is false precision. For international trade and technical specifications, SI units (meters, kilograms, liters) are the standard. US customary units (feet, pounds, gallons) differ from Imperial UK units: 1 US gallon = 3.785 L vs. 1 UK gallon = 4.546 L.