Microsoft Outlook AlternativesOnly Free apps categorised as Calendar Apps

The best free Calendar alternative to Microsoft Outlook is Thunderbird, which is also Open Source. If that doesn't suit you, our users have ranked more than 100 alternatives to Microsoft Outlook and many of them are free Calendar Apps so hopefully you can find a suitable replacement. Other interesting free Calendar App alternatives to Microsoft Outlook are Evolution, eM Client, Betterbird and Spark Mail.

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Microsoft Outlook alternatives are mainly Calendar Apps, but if you're looking for Email Clients or Todo List Managers you can filter on that. Other popular filters include EU, Linux, Open Source, Windows + Free, Android, Windows + Open Source and Free. You can also filter by region, for example EU-based alternatives if you prefer software developed in the European Union. These are just examples - use the filter bar below to find more specific alternatives to Microsoft Outlook.
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Alternatives list

  1. Thunderbird icon

    Thunderbird

     2549 likes

    Cross-platform email client supporting multiple identities, chat, and strong filtering. Extend functionality with add-ons like RSS/Atom feed readers and PGP support.

    87 Thunderbird alternatives

    Cost / License

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • BSD
    • AppImageHub
    • Snapcraft
    • Flathub
    • PortableApps.com
    • F-Droid
    • Haiku
    • Homebrew
    • Chocolatey
    Thunderbird screenshot 1
     
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    15
    Thunderbird vs Microsoft Outlook Comments
    Top Positive Comment
    John Fastman
    12

    Despite its age, Thunderbird remains the most fully featured email client out there. Various add-ons can extend its functionality, it (now) has a built in calendar and, unlike Outlook, it's free, open source and respects your privacy.

    Top Negative Comment
    Guest
    15

    The interface is just impossible for many people to use.

    Review by a new / low-activity user.
    Shaz Shah
    Positive
    0

    I remember when I first used Thunderbird, many years ago, as I'd rather have a single interface for productivity. But the interface through me off and I never got on with the editor. Coming back to it now, it's fresher and smoother. Absolutely love it. In my opinion this is the only true alternative to Outlook. Then there's the bonus of extensions to further enhance it. Though, I'd like to see further improvements to the calendar integration.

    3 of 15 comments
    • Thunderbird is Free and Open SourceMicrosoft Outlook is Paid and Proprietary
    • Thunderbird is Customizable and Privacy focusedMicrosoft Outlook is not according to our users
  2. Evolution icon

    Evolution

     207 likes

    Evolution is a personal information management application that provides integrated mail, calendaring, address book and task list functionality.

    70 Evolution alternatives

    Cost / License

    Application types

    Platforms

    • Linux
    • BSD
    • Flathub
    • S/MIME
    • GNOME
    • OpenPGP
    Mail
     
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    6
    Evolution vs Microsoft Outlook Comments
    Top Positive Comment
    Guest
    2

    It runs on Linux and you still have content if you are offline.

    Review by a new / low-activity user.
    gifford
    Positive
    0

    I can just find everything instantly, Outlook I'm having to go to Chat GPT to research where the option is hidden!

    Guest
    Positive
    -1

    This would be the best alternative, except that it requires the Gnome desktop, so users of other desktop environments need to look elsewhere.

    Review by a new / low-activity user.
    3 of 6 comments
    • Evolution is Free and Open SourceMicrosoft Outlook is Paid and Proprietary
  4. eM Client icon

    eM Client

     233 likes

    eM Client is a full featured e-mail client with a modern and easy to use interface. eM Client also offers calendar, tasks, contacts, notes and chat.

    62 eM Client alternatives

    Cost / License

    • Freemium
    • Proprietary

    Application types

    Platforms

    • Mac
    • Windows
    • Android
    eM Client: Inbox view
     
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    5
    eM Client vs Microsoft Outlook Comments
    Top Positive Comment
    hellih
    0

    It is not very overcomplicated! Very simple, but functional design. therefore also very easy to set up and use.

    Guest
    Positive
    0

    Supports 365 Shared Mailboxes.

    Review by a new / low-activity user.
    Guest
    Positive
    1

    One of the only fully integrated email and calendar solutions that supports Office365, Exchange, Outlook, Gmail, GSuite, POP, and IMAP. Good performance and usability.

    Review by a new / low-activity user.
    3 of 5 comments
    • eM Client is Freemium and ProprietaryMicrosoft Outlook is Paid and Proprietary
  5. Betterbird icon

    Betterbird

     74 likes

    Betterbird, a soft fork of Mozilla Thunderbird, improves user experience with advanced features, bug fixes, security patches, and multi-row descriptions similar to Outlook. Compatible with multiple platforms and can be used alongside Thunderbird, sharing the same profile.

    30 Betterbird alternatives

    Cost / License

    • Free
    • Open Source

    Application type

    Platforms

    • Mac
    • Windows
    • Linux
    • Flathub
    • Chocolatey
    Betterbird screenshot 1
     
  6. Spark Mail icon

    Spark Mail

     138 likes

    E-mail app with all the great features: swipes (long/short), snooze, add (multiple) attachments from the cloud, support for various e-mail services and more.

    62 Spark Mail alternatives

    Cost / License

    • Freemium
    • Proprietary

    Application type

    Platforms

    • Mac
    • Windows
    • Android
    • iPhone
    • iPad
    • Apple Watch
    Spark Mail screenshot 1
     
    |
    1
    Spark Mail vs Microsoft Outlook Comments
    Guest
    Positive
    -1

    Nice client. Great UI. It does lack Caldav support unfortunately.

    Review by a new / low-activity user.
    • Spark Mail is Freemium and ProprietaryMicrosoft Outlook is Paid and Proprietary
  7. Claws Mail icon

    Claws Mail

     106 likes

    Email and news client on GTK+ foundation featuring quick performance, extensible plugins, secure protocols, advanced filtering, strong folder and contact management, lightweight design, powerful search, customizable interface, multi-language support, and encryption.

    63 Claws Mail alternatives

    Cost / License

    • Free
    • Open Source

    Application types

    Platforms

    • Windows
    • Linux
    • BSD
    The main window
     
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    1
    Claws Mail vs Microsoft Outlook Comments
    Guest
    Negative
    -2

    Claws Mail is email only, does not have many of the features of Outlook. Displaying HTML mail is sketchy at best.

    Review by a new / low-activity user.
    • Claws Mail is Free and Open SourceMicrosoft Outlook is Paid and Proprietary
    • Claws Mail is Lightweight, Customizable and Privacy focusedMicrosoft Outlook is not according to our users
  9. Canary Mail icon

    Canary Mail

     29 likes

    Canary can write your emails, prioritize what needs attention, silence spam & much more. Say hello to your Inbox Copilot!

    Cost / License

    • Freemium
    • Proprietary

    Application type

    Platforms

    • Mac
    • Windows
    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Apple Watch
    iOS-1
     
  10. EssentialPIM icon

    EssentialPIM

     76 likes

    The powerful, full-featured Personal Information Manager for Windows offering Email, Synchronization, Portability, Network support, Android and iOS versions.

    176 EssentialPIM alternatives

    Cost / License

    • Freemium
    • Proprietary

    Application types

    Platforms

    • Windows
    • Android
    • iPhone
    EssentialPIM screenshot 1
     
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    1
    EssentialPIM vs Microsoft Outlook Comments
    Guest
    Positive
    -1

    Tricky to configure. Does not speak MAPI, but many Cloudservices. I was not successful to synchronize OwnCloud

    Review by a new / low-activity user.
    • EssentialPIM is Freemium and ProprietaryMicrosoft Outlook is Paid and Proprietary
  12. Apple Calendar icon

    Apple Calendar

     144 likes

    Keep track of your busy schedule and share it with others using Calendar. Create separate calendars — one for home, another for school, a third for work, and so on. See all your calendars in a single window or choose to see only the calendars you want.

    102 Apple Calendar alternatives

    Cost / License

    • Free
    • Proprietary

    Application type

    Platforms

    • Mac
    • iPhone
    • iPad
    • iCloud
    Apple Calendar screenshot 1
     
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    5
    Apple Calendar vs Microsoft Outlook Comments
    Top Negative Comment
    Guest
    1

    it's a calendar app not a email client!

    Review by a new / low-activity user.
    Guest
    Negative
    0

    Apple Calendar is a Calendar. It's a minimal part of what Outlook mail client provides.

    Review by a new / low-activity user.
    Guest
    Negative
    0

    outlook its not just calendar

    Review by a new / low-activity user.
    3 of 5 comments
    • Apple Calendar is Free and ProprietaryMicrosoft Outlook is Paid and Proprietary
  13. Zimbra Desktop icon

    Zimbra Desktop

     32 likes

    The free Zimbra Desktop client allows you to meld the online and offline worlds – storing and synching your email, calendar, contacts, files and documents in the cloud, yet having them locally accessible when on the road.

    54 Zimbra Desktop alternatives

    Cost / License

    • Free Personal
    • Proprietary

    Application types

    Platforms

    • Mac
    • Windows
    • Linux
    Zimbra Desktop screenshot 1
     
12 of 39 Microsoft Outlook alternatives