Lux to Foot Candle Calculator

Understanding Lux and Foot Candles: Light Measurement Units

Light measurement is crucial in various fields including photography, architecture, lighting design, and workplace safety. Two of the most commonly used units for measuring illuminance (the amount of light falling on a surface) are lux and foot candles. Understanding the relationship between these units is essential for accurate lighting calculations and conversions.

What is Lux?

Lux (lx) is the SI (International System of Units) unit of illuminance. It measures the amount of light that falls on a surface. One lux is defined as one lumen per square meter (lm/m²). Lux is widely used in scientific and international contexts, particularly in Europe and most of the world.

What are Foot Candles?

Foot candles (fc) are a non-SI unit of illuminance commonly used in the United States. One foot candle is defined as one lumen per square foot (lm/ft²). This unit is primarily used in the United States for lighting calculations in architecture, photography, and workplace lighting standards.

Conversion Formula

The conversion between lux and foot candles is based on the relationship between square meters and square feet:

Lux to Foot Candles: 1 lux = 0.092903 foot candles

Foot Candles to Lux: 1 foot candle = 10.764 lux

The conversion factor comes from the fact that 1 square meter equals approximately 10.764 square feet, so the relationship is: 1 lux = 1 lumen/m² = 1 lumen/(10.764 ft²) = 0.092903 lumen/ft² = 0.092903 foot candles.

Practical Applications

Photography

Photographers use these measurements to determine proper exposure settings. Different lighting conditions require different illuminance levels:

Direct sunlight: 100,000 lux (9,290 foot candles)
Overcast day: 1,000 lux (93 foot candles)
Office lighting: 500 lux (46 foot candles)
Home lighting: 50-200 lux (5-19 foot candles)

Workplace Safety

Occupational safety standards specify minimum illuminance levels for different work environments:

General office work: 500 lux (46 foot candles)
Detailed work: 1,000 lux (93 foot candles)
Precision work: 2,000 lux (186 foot candles)

Architecture and Interior Design

Architects and lighting designers use these measurements to create appropriate lighting schemes for different spaces, ensuring both functionality and energy efficiency.

How to Use This Calculator

Our lux to foot candle calculator makes it easy to convert between these two units:

Select the conversion direction (lux to foot candles or foot candles to lux)
Enter the value you want to convert
The result will be displayed automatically
Use the "Swap Values" button to quickly switch between conversion directions
Use "Clear All" to reset the calculator

Common Conversion Examples

Lux (lx)	Foot Candles (fc)	Typical Use Case
1	0.0929	Very dim lighting
100	9.29	Dim room lighting
500	46.45	Office lighting
1,000	92.90	Good office lighting
10,000	929.03	Bright daylight

Frequently Asked Questions

What is the difference between lux and foot candles?

Lux and foot candles are both units of illuminance (light falling on a surface), but lux is the SI unit (lumen per square meter) while foot candles are the imperial unit (lumen per square foot). The main difference is the area unit used in the calculation.

Which unit should I use - lux or foot candles?

Use lux if you're working in scientific, international, or European contexts. Use foot candles if you're working in the United States, particularly in architecture, photography, or workplace lighting standards. Many professionals are familiar with both units.

How accurate is the conversion between lux and foot candles?

The conversion is mathematically precise: 1 lux = 0.092903 foot candles and 1 foot candle = 10.764 lux. This calculator provides results with 6 decimal places for maximum precision.

What are typical lux values for different environments?

Typical values include: direct sunlight (100,000 lux), overcast day (1,000 lux), office lighting (500 lux), home lighting (50-200 lux), and moonlight (0.1 lux). These values can vary significantly based on specific conditions.

Can I use this calculator for professional lighting design?

Yes, this calculator provides accurate conversions suitable for professional use. However, for complex lighting design projects, you may also need to consider factors like light distribution, color temperature, and specific application requirements.

Report Tool or Give Us Suggestions