Google Calendar is the best calendar app for Android due to its ease of use, seamless integration with Google's ecosystem, and free personal use option. Microsoft Outlook is a great alternative for Exchange users and Microsoft loyalists, offering syncing options with Exchange servers, clean design, and free mobile usage. aCalendar is ideal for those who want high customization options, including widgets and hybrid views, while DigiCal offers a friendly user interface and balance between ease of use and customization. Any.do combines task lists with calendars, helping users schedule tasks, while Business Calendar 2 provides easy-to-tweak appointment views on the fly and natural language processing. Proton Calendar is an excellent choice for those prioritizing privacy, offering fully encrypted calendar syncing. Ultimately, the best app depends on individual preferences and needs, making it essential to try a few options before selecting one.