Illuminance Converter
Quickly convert between light intensity units like lux and foot-candles.
Why Use This Tool? ✅
Fast & Accurate
Get precise conversions in real-time based on standardized conversion factors.
Supports All Common Units
Easily convert between lux, foot-candles, phot, and other relevant illuminance units.
Perfect for Professionals
An essential tool for photographers, lighting designers, architects, and scientists.
User-Friendly Interface
A simple, clean interface that makes converting any illuminance unit quick and easy.
Measuring Light: A Guide to Illuminance Units 💡
In photometry, illuminance is the total luminous flux incident on a surface, per unit area. In simpler terms, it's a measure of how much light is falling onto a surface. This is different from luminance, which is the light emitted *from* a surface. Illuminance is a crucial measurement in lighting design, photography, and ensuring safe and comfortable environments.
The SI Unit: Lux (lx)
The standard international (SI) unit for illuminance is the lux (lx). It is equal to one lumen per square meter (lm/m²). For context, a brightly lit office might have an illuminance of around 500 lux, while direct sunlight can exceed 100,000 lux.
The Imperial Unit: Foot-candle (fc)
The foot-candle (fc) is the corresponding unit in the Imperial and US customary systems. It is equal to one lumen per square foot (lm/ft²). Because a square meter is larger than a square foot, one foot-candle is a larger amount of illuminance than one lux (1 fc ≈ 10.764 lx). This unit is still widely used in the United States, particularly in lighting for film, theater, and architecture.
Other Scientific Units
- Phot (ph): The CGS (centimetre–gram–second) unit of illuminance, equal to one lumen per square centimeter. 1 phot = 10,000 lux.
- Nox: An older unit used for measuring very low levels of illuminance. 1 nox = 0.001 lux.
Why is Conversion Important?
With different standards used across the world and in different industries, a reliable converter is essential. A lighting designer from Europe working on a project in the US will need to convert their lux specifications to foot-candles to communicate with local contractors. A photographer using an old light meter might need to convert its readings to modern standards. This tool provides a seamless way to translate between all these units, ensuring accuracy and clarity in any project.