Convert lumen/square foot [lm/ft^2] to meter-candle [m*c] Online | Free lllumination Converter

Measuring Illuminance

Lumen per square foot (lm/ft²) is a unit of illuminance, representing the amount of luminous flux (light) falling on a surface area of one square foot. It measures how brightly an area is illuminated, helping to quantify the perceived brightness for human vision.

This unit is commonly used in lighting design, architecture, and workplace safety to ensure adequate and comfortable lighting conditions. For example, offices, classrooms, and public spaces have recommended illuminance levels expressed in lm/ft² to optimize visibility and reduce eye strain.

Illuminance measured in lm/ft² is closely related to the SI unit lux, which is lumens per square meter (lm/m²). Since one square foot equals approximately 0.0929 square meters, 1 lm/ft² is about 10.76 lux.

Designers use lm/ft² to plan lighting layouts, select appropriate fixtures, and evaluate energy efficiency. Proper illuminance levels contribute to productivity, safety, and aesthetics by ensuring spaces are neither too dim nor overly bright.

Understanding lumen per square foot helps balance lighting quality and energy consumption, making it a vital concept in modern lighting engineering.

A Traditional Unit of Illuminance

The meter-candle (m·c) is a historical unit of illuminance that measures the luminous flux falling on a surface area of one square meter from a uniform point source with an intensity of one candlepower (now replaced by the candela) placed one meter away. It was used primarily before the international adoption of the lux as the standard unit for illuminance.

One meter-candle is roughly equivalent to one lux, since lux is defined as lumens per square meter. However, the meter-candle historically provided a more intuitive measure of illuminance based on the distance from a known light source, which was practical for early lighting calculations and designs.

While the meter-candle is largely obsolete today, replaced by the lux in most scientific and engineering applications, it remains a useful reference when interpreting older lighting standards, manuals, and specifications.

Understanding the meter-candle helps in grasping the evolution of lighting measurement units and appreciating the advances in photometric science that have led to more precise and standardized units.