Lumen to Lux Calculator

What are Lumens and Lux?

Lumen (lm) is the SI derived unit of luminous flux, which measures the total amount of light emitted by a source in all directions. Lux (lx) is the SI derived unit of illuminance, which measures the amount of light that falls on a surface area.

The Lumen to Lux Formula

The formula for converting lumens to lux is:

\[E = \frac{\Phi}{A}\]

Where:

• \(E\) = Illuminance (lux)
• \(\Phi\) = Luminous flux (lumens)
• \(A\) = Area (square meters)

Step-by-Step Lumen to Lux Calculation

1. Identify the luminous flux in lumens (\(\Phi\)) and the area in square meters (\(A\)).
2. If the area is given in square feet, convert it to square meters by multiplying by 0.092903.
3. Apply the formula: \(E = \frac{\Phi}{A}\).
4. The result is the illuminance in lux (\(E\)).

Example Calculation

Let's calculate the illuminance for a light source with 1000 lumens over an area of 100 square feet:

1. \(\Phi = 1000 \text{ lm}\), \(A = 100 \text{ ft}^2\)
2. Convert area to square meters: \(100 \text{ ft}^2 \times 0.092903 = 9.2903 \text{ m}^2\)
3. \[\begin{align} E &= \frac{\Phi}{A} \\ &= \frac{1000 \text{ lm}}{9.2903 \text{ m}^2} \\ &\approx 107.64 \text{ lux} \end{align}\]

Visual Representation

This diagram illustrates how 1000 lumens of light spread over an area of 9.2903 square meters results in an illuminance of approximately 107.64 lux. The yellow circle represents the distribution of light, with the lumen value at the center and the resulting lux value at the bottom.