Browse free open source Calendar software and projects for Windows below. Use the toggles on the left to filter open source Calendar software by OS, license, language, programming language, and project status.

  • Gemini 3 and 200+ AI Models on One Platform Icon
    Gemini 3 and 200+ AI Models on One Platform

    Access Google's best plus Claude, Llama, and Gemma. Fine-tune and deploy from one console.

    Build generative AI apps with Vertex AI. Switch between models without switching platforms.
    Start Free
  • Try Google Cloud Risk-Free With $300 in Credit Icon
    Try Google Cloud Risk-Free With $300 in Credit

    No hidden charges. No surprise bills. Cancel anytime.

    Use your credit across every product. Compute, storage, AI, analytics. When it runs out, 20+ products stay free. You only pay when you choose to.
    Start Free
  • 1
    The VCS to ICS Calendar Converter allows you to convert VCALENDAR files (for example generated by Nokia nbuexplorer or Microsoft Works) to the newer iCalendar format, used by Android and iOS for example. It allows the parsing of events and todo's.
    Leader badge
    Downloads: 28 This Week
    Last Update:
    See Project
  • 2
    The Mozilla Sunbird Portable Edition project is now part of the PortableApps.com project: http://sourceforge.net/projects/portableapps
    Downloads: 3 This Week
    Last Update:
    See Project
  • 3
    OpenCustomer is a Web-based customer relationship managment (CRM) application, using Mysql and Java/Tomcat. (Online Demo available)
    Downloads: 1 This Week
    Last Update:
    See Project
  • 4
    CalendarTechnique is a feature rich customizable web calendaring and scheduling application with support for group/shared calendars. CalendarTechnique makes it easy to manage events, tasks and journal entries as well as import and export iCalendar files.
    Downloads: 0 This Week
    Last Update:
    See Project
  • MongoDB Atlas runs apps anywhere Icon
    MongoDB Atlas runs apps anywhere

    Deploy in 115+ regions with the modern database for every enterprise.

    MongoDB Atlas gives you the freedom to build and run modern applications anywhere—across AWS, Azure, and Google Cloud. With global availability in over 115 regions, Atlas lets you deploy close to your users, meet compliance needs, and scale with confidence across any geography.
    Start Free
  • 5
    The Crosswise project is a web-based community event calendar that adds modular data analysis and visualization, and communication methods, to provide community organizations with a powerful event planning, collaboration and analysis tool.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 6
    A multiuser Diary Management System that will enable staff in organisations to set/update/view meetings and appointments. The system will operate via a central server, but clients will able to function offline. It will support Mac OSX/Windows/*nix
    Downloads: 0 This Week
    Last Update:
    See Project
  • 7
    The lightning-exchange-provider addon allows you to use Microsoft Exchange calendars in Thunderbird, via Exchange’s web services. The addon works on Thunderbird 3.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 8
    Spicebird is an open-source email and collaboration suite based on the Mozilla platform. It provides integrated e-mail, contacts, calendaring and instant messaging. It can connect to any SMTP/IMAP email server, CalDav Calendar server and Jabber serve
    Downloads: 0 This Week
    Last Update:
    See Project
  • 9
    OpenJean is a cross-platform, extensible, personal information manager. It includes: file manager, RSS aggregator, calendar and appointments diary, mailer, image manager, multimedia manager, favorites, notes, tasks, anniversaries, topics and address book
    Downloads: 0 This Week
    Last Update:
    See Project
  • Forever Free Full-Stack Observability | Grafana Cloud Icon
    Forever Free Full-Stack Observability | Grafana Cloud

    Our generous forever free tier includes the full platform, including the AI Assistant, for 3 users with 10k metrics, 50GB logs, and 50GB traces.

    Built on open standards like Prometheus and OpenTelemetry, Grafana Cloud includes Kubernetes Monitoring, Application Observability, Incident Response, plus the AI-powered Grafana Assistant. Get started with our generous free tier today.
    Create free account
  • Previous
  • You're on page 1
  • Next
MongoDB Logo MongoDB