Calendar Converter is an Android application that helps users to convert dates between different calendars such as Gregorian, Julian, French Republican, Muslim, and Jewish calendars. It is a free utility and tool application developed by Rémy Pialat that makes date conversion easy and hassle-free.

With Calendar Converter, users can enter a date in any of the supported calendars and the app will instantly convert the date into the other calendars. The app also offers different buttons to navigate through dates easily. Furthermore, it provides the date of transition between Julian and Gregorian calendars for different countries.

One of the unique features of this app is that it displays the dates of the main Christian, Muslim, and Jewish holidays for a given year. Additionally, the app offers a configurable widget to display the date of the day in the calendar of your choice, and a Wear OS app to display the date of the day in the calendar of your choice on your Android watch.

Overall, Calendar Converter is a comprehensive tool for date conversion that is easy to use and provides accurate results. It is a must-have app for anyone who deals with different calendars and needs to convert dates quickly and efficiently.