Google Calendar is a free time-management and scheduling calendar service developed by Google. It allows users to create and edit events, set reminders, and share calendars with others. Key features include:

• Event scheduling with customizable notifications
• Integration with Gmail to automatically add events from emails
• Multiple calendar support for personal, work, and shared use
• Sync across devices including smartphones, tablets, and computers
• Sharing and collaboration tools for teams and families
• Access to public calendars for holidays, sports schedules, and more

Google Calendar is accessible via web browsers and mobile apps for Android and iOS, helping users stay organized and manage their time effectively.