Convert nox to foot-candle [ft*c, fc] Online | Free lllumination Converter

A Unit of Illuminance in Historical Use

Nox is an older, less commonly used unit of illuminance that measures the intensity of light falling on a surface. It is defined as one millilumen per square meter (1 mLm/m²) or equivalently, 0.001 lux. This means 1 nox is equal to one-thousandth of a lux.

The term “nox” comes from the Latin word for “night,” reflecting its use in describing very low levels of light, such as nighttime or dim environments. Although it is rarely used in modern lighting science, the nox still appears in some older literature and niche applications where extremely low light levels are important.

Understanding nox helps provide context for measuring and comparing very faint light intensities. For example, the illumination from a full moon on a clear night is roughly around 0.1 lux, or 100 nox.

While modern standards primarily use lux as the universal unit of illuminance, knowing about nox can be helpful when reading historical documents or dealing with precise measurements in low-light scenarios.

A Unit of Illuminance

The foot-candle (ft·c or fc) is a unit of illuminance used primarily in the United States and some other countries that follow imperial measurements. It measures the amount of luminous flux (light) falling on a surface of one square foot. One foot-candle is defined as one lumen per square foot.

Foot-candles are commonly used in lighting design, architecture, photography, and workplace safety to ensure spaces have appropriate lighting levels. For example, an office workspace typically requires around 30 to 50 foot-candles to provide sufficient brightness for tasks without causing eye strain. Retail stores and hospitals may require higher levels, while hallways or staircases might have lower standards.

Foot-candles are related to the metric unit lux, where 1 foot-candle equals approximately 10.76 lux (lumens per square meter). Understanding foot-candle measurements allows designers and engineers to plan lighting layouts effectively, balancing energy use with visual comfort.

Despite the growing global adoption of the lux, foot-candles remain prevalent in industries and regions that use imperial units, making it important for professionals to be familiar with both.