A simple HTML-based tool for converting between decimal, binary, octal, and hexadecimal number systems. This open-source converter is licensed under the Apache 2.0 License. While the interface is currently in French, you can easily modify the code to display text in any language.
Below, a screenshot of this HTML code working:
Download the .zip file, extract the files inside and then, simply double click on "index.html" to open the file (the app) into your preferred browser.
Once you are using the app, you simply introduce any number into the text box and convert it by simply clicking the "Convert" button. Wait for the results! (they show instantly)