Calndars is the best app to converts dates between the most used calendars in the world.
Select a calendar to set a date, and get the corresponding date in another calendar.
Copy the date to use it in another app.
Add a calendar to the favourites by tapping the star.
Add a calendar to the widgets by tapping the 4 squares icon.
Calendars can be reordered in the list.

The app supports small, medium and large widgets.
Create a Shortcut in the Apple's Shortcuts App and use the Shortcut everywhere.
Use AppleScript on MacOS for integration between Calndars and other Apps.

Calendars to convert between are:
- Buddhist
- Chinese
- Coptic
- Ethiopic (Amete Alem)
- Ethiopic (Amete Mihret)
- Gregorian
- Hebrew
- indian
- Islamic Civil
- Islamic Tabular
- Islamic Umm Al Qura
- Japanese
- Persian
- Taiwanese

Available for iPhone, iPad, Mac and AppleWatch.