Light Meter

Measures light (RGB) & luminance via your device camera!



A handy and easy-to-use app to measure the light RGB components and luminance level inside your browser. The app uses your device camera to capture light and then processes the data with Canvas API in JavaScript.


This web application is designed to measure the environment light (in RGB format) and luminosity with HTML5 tools. The app uses the Canvas API which is supported in all modern browsers to compute the real-time RGB and light luminance level. Please wait for this web app to load completely, then accept the camera permission to allow the app to capture real-time video and initializes the underlying engine. Once the engine is fully loaded, you can see the real-time RGB and Luminance in a colored graph. Within the graph, the left side is for the luminance level and the right side shows the RGB level. The X-axis shows the active time frame for the last 30 seconds. The graph is colored with red, green, and blue lines for the RGB colors and yellow lines for the luminance level. On the top toolbar, you can see the color, luminance, duration, and three settings to customize the app. The first value to customize is the update interval which is set to 250 milliseconds by default. Increasing or decreasing this value will affect the graph update speed. The second value is for the calibration constant. In some environments, you may need to add a calibration constant to the RGB values to make them more accurate. By default, this value is zero. Please note that reloading the app will reload the light meter engine and you will need to wait for the app to completely loads before seeing the light level data again.

To work with this web application, simply load this page and wait for the app to initialize. Once loading finishes, real-time data will be shown in the above graph. The graph has four colored lines to represent the real-time RGB and luminance levels. Moreover, these values are also rendered on top of the graph with a large font size. Please note that this app needs camera permission on your device. Therefore if you deny the permission or if your device does not have a camera, you won't be able to work with this web application.

Light Meter app is also available as a browser extension. As an extension, this app does not need an internet connection and can be used offline in your browser. Download links for three popular browsers are as follows: Chrome, Opera, Edge.

If you found a bug in this page, or have a feature/function which you would like to see in this web app, please let us know by sending an email or through the discussion form below. Moreover, don't forget to check other web apps in webbrowsertools.com, we have many useful apps related to browser's privacy and security.

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