Lux
Lux is the SI unit of illuminance. One lux means that one lumen of luminous flux is distributed across one square metre of surface area.
Understanding light levels
What Is Illuminance?
Illuminance measures the amount of visible light falling on a surface. It helps describe how brightly a desk, floor, road, room or outdoor area is illuminated.
Foot-Candle
A foot-candle measures one lumen of light spread across one square foot. It is commonly used in the United States for building and workplace lighting.
Simple conversion
How to Use the Illuminance Converter
The tool calculates your result automatically whenever you enter a number or change either unit.
Enter the light level
Type the illuminance measurement you want to convert into the value field.
Select the original unit
Choose lux, foot-candle, phot, nox or another supported illuminance unit.
Choose the result unit
Select your required output unit and view the converted result immediately.
Unit relationships
Common Illuminance Conversions
These standard relationships can help you understand and verify common lighting calculations.
| Starting Unit | Equivalent Unit | Converted Value |
|---|---|---|
| 1 lux | Foot-candles | 0.092903 fc |
| 1 foot-candle | Lux | 10.7639 lx |
| 1 kilolux | Lux | 1,000 lx |
| 1 phot | Lux | 10,000 lx |
| 1 nox | Lux | 0.001 lx |
| 1 lux | Lumens per square metre | 1 lm/m² |
Example lighting levels
Typical Illuminance Examples
Actual requirements depend on the activity, environment, local standards, surface colours and lighting design.
Low outdoor lighting
Moonlight, dark walkways and low-level landscape illumination.
General circulation
Corridors, entrance areas and basic background lighting.
Office and study areas
Common lighting range for reading, writing and computer-based work.
Detailed visual work
Inspection, technical drawing and other visually demanding tasks.
Helpful answers
Frequently Asked Questions
Illuminance measures how much visible light reaches a surface. It is commonly measured in lux or foot-candles.
One foot-candle is approximately equal to 10.7639 lux. To convert foot-candles to lux, multiply the value by 10.7639.
Multiply the lux value by approximately 0.092903, or divide the lux value by 10.7639, to obtain foot-candles.
Lumens measure the total visible light emitted by a source. Lux measures how much of that light reaches each square metre of a surface.
Yes. One lux is exactly equal to one lumen per square metre. These expressions describe the same illuminance value.
A phot is a CGS illuminance unit equal to one lumen per square centimetre. One phot equals 10,000 lux.
Some phones can provide approximate readings using their light sensor. For professional or compliance-related measurements, a calibrated lux meter is more reliable.
Measurement note:
This converter changes illuminance units only. It does not
measure the actual light level in a room or determine
compliance with local workplace or building standards.