Top Alternatives to Google Calendar

Lightning is a comprehensive calendar and task management add-on for Mozilla Thunderbird and Seamonkey, designed to integrate seamlessly with email. It offers robust features for scheduling, task tracking, and synchronization with various online calendar services, enhancing productivity directly within your email client.

Rainlendar is a highly customizable calendar application for Windows, macOS, and Linux. It seamlessly integrates with popular online calendars like Google Calendar and Fantastical, offering comprehensive event and task management directly on your desktop.

Kolab Community is a comprehensive, free, and open-source groupware suite designed for collaborative work. It provides integrated email, calendar, contacts, and tasks functionalities, empowering individuals and teams to communicate and manage their data efficiently and with a strong focus on data privacy.

Kontact is a comprehensive personal information management suite from KDE combining email, contacts, calendar, tasks, and news in one integrated application. It offers robust synchronization options and supports various protocols.

Jorte is a comprehensive calendar and organizer application designed to help users manage their schedules, tasks, and notes efficiently across multiple devices. It offers a flexible and customizable interface to suit individual preferences and integrates with popular calendar services.

Business Calendar is a robust and feature-rich calendar application designed specifically for users who need a powerful and organized way to manage their schedules, events, and tasks. It offers a clear overview of appointments, integrated task management, and extensive customization options to cater to demanding professional needs.

fruux is a robust cross-platform synchronization service designed to keep your contacts, calendars, and tasks seamlessly in sync across all your devices and applications. It offers a secure and reliable cloud platform with strong privacy focus, ideal for individuals and teams needing consistent data access and collaboration.

Calvetica is a highly-regarded calendar and time management application designed specifically for iPhone and iPad, praised for its speed and intuitive user interface to quickly create, view, and manage events.

Etar is a free and open-source material design calendar application for Android, prioritizing privacy and a clean user experience. It focuses on core calendar functionalities like event management and reminders, offering data export/import and syncing capabilities without ads or excessive features.

VueMinder Calendar is a comprehensive calendar and task management application for Windows, designed to help users organize their schedules and boost productivity. It offers a wide range of features including robust synchronization options, customizable views, and advanced reminder capabilities, making it suitable for both personal and professional use.

Holiline Reminder is a free, multi-language calendar and organizer for Windows, designed to help users manage events, deadlines, tasks, and notes efficiently. It includes features like recurring tasks, an address book, and a built-in calendar, offering a straightforward approach to staying organized.

Microsoft Calendar, part of the Outlook suite, is a robust online calendaring platform designed for scheduling, organization, and collaboration. It allows users to manage appointments, events, and tasks effectively, integrate with other services, and share schedules with others.

Microsoft Mail and Calendar is the default email and calendar client included with Windows, providing integrated tools to manage your communications and schedule.

KOrganizer is a comprehensive calendar and scheduling application, part of the integrated KDE Kontact suite. It provides robust tools for managing events, tasks, and deadlines, with extensive connectivity options and customization.

BusyCal is a powerful desktop calendar application for Mac, designed to enhance productivity and organization. It offers a robust set of features for managing events, tasks, and reminders, with seamless integration across various calendar services like iCloud, Google Calendar, and Exchange.

MIDAS is a comprehensive web-based room and resource scheduling software designed for organizations of all sizes. It facilitates efficient management of spaces, equipment, and staff, streamlining the booking process and preventing conflicts.

FCorp My Calendar is a lightweight and portable personal information manager designed for organizing your daily life. It helps you manage your diary entries, notes, schedules, birthdays, and to-do lists efficiently, all within a simple and user-friendly interface.

aCalendar is a feature-rich calendar and task management application designed for users who need robust synchronization, detailed event management, and a user-friendly interface.