Lux to Foot Candles Converter

Lux and foot candles are commonly used units for measuring illuminance — specifically, the amount of light a surface receives. These units will tell you how bright or dark a room feels, and their value will depend on the light source's lumens and position.

While lux and foot candles both measure the light intensity in a room, they do so based on two different units:

• Lux quantifies the amount of light in one square meter and is the internationally accepted illuminance unit used worldwide.
• Foot candles express the amount of light in one square foot and are used mainly in the United States.

Understanding the distinction between these units is essential when designing lighting setups, calculating appropriate illumination levels, or assessing light sources' efficiency.

💡 To find out the recommended lux and foot candle values for different ambients and calculate the required lumens for your light bulbs, check out our lighting calculator.

What does 'lumen' mean, and how does it relate to lux and foot candles?

Lumens are key to quantifying the brightness or luminosity of a light source. Whereas lux and foot candles represent the amount of light a certain surface receives, lumens represent the amount of light that a certain light source emits. It comprises all light emitted by the source, spreading in all directions.

Understanding the relationship between lumens, lux, and foot candles is paramount when comprehending how a light source's brightness translates into the level of illumination experienced on a surface.

As the lumen of a light bulb increases, the corresponding lux and foot candle values also increase because a more light reaches the target surface. This intricate interplay assumes particular significance when considering the positioning of the light source in relation to the illuminated surface.

For example, consider setting up a light bulb at 1, 2, and 4 meters above a target surface area. To maintain the same lux in all regions, the lumen would need to increase proportionately.

Consequently, when determining lighting requirements, it's vital to carefully consider both lumens and the specific placement of light sources so that you can achieve the desired illumination level.

💡 For more information on lumen vs. lux and light source distance, you can check out our lumen calculator.

Lux and foot candles are units used to measure illuminance — specifically the amount of light received per unit area. We utilize the conversion factor derived from the square meters to square feet ratio to convert lux to foot candles.

So how do we convert lux to foot candles? We do as follows:

We know that 1 square meter equals 10.76391 square feet. Similarly, 1 lux represents the illuminance of 1 lumen per square meter. Therefore, to do a lux to foot candles conversion, we divide the lux value by the conversion factor:

Where:

• fcfc is the illuminance in foot candles; and
• lxlx is the illuminance in lux.

For example, if you have an illuminance measurement of 100 lux, you can convert it to foot candles as approximately 9.29 foot candles.

Conversely, if you need to convert foot candles to lux, you can multiply the foot candle value by the conversion factor:

Understanding lux-to-foot-candle and foot-candle-to-lux conversions allow you to communicate illuminance measurements in different settings effectively. Whether you're working with international standards using lux or you need to work with foot candles, these conversions enable you to make informed decisions about lighting conditions.

If you'd like to learn more about this topic or are curious about the relationship between illuminance and electric power, check out our watts to lux calculator. There you will learn about luminous efficacy and the different types of light bulbs available. Furthermore, you will also be able to calculate the amount of power needed to obtain a certain amount of lux for a given area and determine the most efficient light bulbs to do this.