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Convert Between Illuminance Units Convert between lux, foot-candles, and phots for lighting measurements.

Illuminance Converter illustration
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Illuminance Converter

Convert between lux, foot-candles, and phots for lighting measurements.

1

Enter illuminance

Type the illuminance value.

2

Select units

Choose between lux, foot-candles, and phots.

3

Read the converted value

Converted illuminance appears instantly.

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What Is Illuminance Converter?

An Illuminance Converter is a tool that translates between units measuring the amount of light falling on a surface, such as lux, foot-candles, and phot. Lighting designers and engineers use it to ensure compliance with building codes, which specify proper illuminance levels for workplaces, schools, hospitals, and outdoor spaces. One specific problem it solves is converting between SI and US units, for example, from lux to foot-candles, which is crucial when working on projects that involve international collaborations or require adherence to local standards.

The tool's configuration includes three units: lux with a factor of 1, foot-candle with a factor of 10.7639104167, and phot with a factor of 10000. This setup allows users to convert between these units easily, addressing issues like how to convert lux to foot-candles or phot. It also references specific conversion rates, such as from lux to foot-candles and vice versa, making it a reliable lighting unit converter.

What makes this tool different is its ability to handle conversions with precision, using predefined factors for each unit, ensuring accurate results when converting between units like lux to phot or foot-candles to lux. Its reference section includes multiple conversion rates, providing a clear mapping of how different units relate to each other, which helps users understand the relationships between these lighting units and perform tasks efficiently.

Why Use Illuminance Converter?

  • Converts between lux and foot-candles for international lighting standards.
  • Essential for architects, lighting designers, and photographers.
  • Includes the phot for legacy reference compatibility.
  • Real-time conversion.

Common Use Cases

Lighting Design

Convert illuminance requirements between lux and foot-candles for international projects.

Photography

Understand light levels for exposure calculations.

Building Codes

Verify workspace lighting meets standards specified in either lux or foot-candles.

Horticulture

Convert light level measurements for indoor growing specifications.

Technical Guide

Illuminance is luminous flux per unit area — how much light hits a surface.

• 1 lux = 1 lumen/m²
• 1 foot-candle = 1 lumen/ft² = 10.764 lux
• 1 phot = 1 lumen/cm² = 10,000 lux

Typical illuminance levels:
• Full moonlight: 0.25-1 lux
• Street lighting: 5-30 lux
• Office lighting: 300-500 lux
• Surgery: 10,000-100,000 lux
• Direct sunlight: 100,000 lux

Do not confuse illuminance (lux, light on a surface) with luminance (cd/m², light from a surface). They measure different aspects of lighting.

Tips & Best Practices

  • 1
    1 foot-candle ≈ 10.76 lux. For quick estimates, multiply fc by 10.
  • 2
    Office lighting should be 300-500 lux (30-50 foot-candles).
  • 3
    A single 60W incandescent bulb provides about 800 lumens.
  • 4
    Illuminance (lux) measures light arriving at a surface; luminance (nits) measures light leaving a surface.

Related Tools

Frequently Asked Questions

Q How many lux in a foot-candle?
One foot-candle equals approximately 10.764 lux.
Q What is the recommended office lighting level?
Most standards recommend 300-500 lux (28-46 foot-candles) for general office work.
Q What is the difference between lux and lumens?
Lumens measure total light output from a source. Lux measures how much of that light reaches a surface. Lux = lumens per square meter.
Q What is a phot?
A phot is the CGS unit of illuminance equal to 10,000 lux (1 lumen per cm²). It is rarely used in modern practice.

About This Tool

Illuminance Converter is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.