Illuminance (Lux) Calculation for Your Rooms

Illuminance (Lux) Calculation for Your Rooms

The illuminance calculation is an important basis for indoor lighting design. With the following online calculator, you can calculate the lux value based on the parameters of an existing or newly planned lighting system.

Illuminance Calculation

The illuminance indicates how much light actually reaches a defined area. In this case the sum of all installed light sources in the whole room matters. While the luminous flux of a luminaire is a transmitting size, the illuminance is a receiving size.

The illuminance has the unit Lux

1 lux (lx) corresponds to a luminous flux of 1 lumen per square meter or 1 lumen per 10.76 square feet.

Illuminance Calculator

In the commercial sector, the requirements for lighting equipment are precisely regulated depending on the visual task. In the private sector, there is no regulation, but there are recommendations for different living spaces. With the following online tool you can calculate the actual illuminance after entering the parameters.

Illuminance Calculator



Room Dimensions


The tools in this website are provided "as is" without any warranty of any kind.


This online calculator helps you to calculate the illuminance in lux. The tool can be used to check or roughly plan lighting installations. However, to take into account all factors, such as the best possible placement of light sources, the optimal distance or the reflection behavior of the room, a professional lighting design is essential.