I'm looking for a calendar application, ideally one that can run on windows, Mac, and iOS. I want my data to be available offline, and -- here's the kicker -- I don't want to store my data on Google's servers, nor Microsoft's, nor Apple's. I want the data for the calendar to be stored locally, under my sole control.

I might then sync the data file myself using dropbox, spideroak, file transporter, or some other system. The point is I don't want my data stored on someone else's servers. under someone else's control.

  • 1
    +1 Essential question. Note: Dropbox and Spideroak store your data on their servers. To avoid that, consider SparkleShare or OwnCloud.
    – Nicolas Raoul
    Apr 10, 2014 at 2:38
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    Good point -- I do know that if I sync via spideroak or dropbox it's on someone else's servers, but I can also control whether it's encrypted or not (using, e.g., Boxcryptor, TrueCrypt...)
    – MM.
    Apr 10, 2014 at 2:50
  • Fastmail just announced Calendar integration. I've been using them for my email over the past year and has been a great experience so far: blog.fastmail.fm/2014/06/23/announcing-the-fastmail-calendar Jun 25, 2014 at 1:28
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    How about Mozilla Lightening (mozilla.org/en-US/projects/calendar)? It's an add-on to Thunderbird. A nice feature is that you can either install it locally, or on a thumb drive and use it anywhere
    – Tymric
    Aug 1, 2014 at 13:11
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    Have you looked in to hosting your own CalDAV server? I know OSX Server has built-in CalDAV support, so you could host it on your own machine. Apple's Calendar app (OSX and iOS) support CalDAV as well, and there's probably one for Windows (although I don't know one offhand).
    – Mike S
    Aug 13, 2014 at 2:43

4 Answers 4


Looks like k5nCal is what you want.

  • Runs on Windows and Mac (it's open source too, so iOS support would need some of your leg work).
  • Stores everything locally, hence you can sync those local files yourself.
  • Works off-line without requiring an Internet connection.

Active Desktop Calendar is a fully customizable calendar with notes, tasks, alarms and contacts provides seamless integration and interactivity with the desktop background. You can organize data in color coded layers and share them in a local network. The program integrates with Outlook to show its appointments/tasks on the desktop and offers connection with Google calendars and web based ICS files. There are preset calendars with holidays for different countries. You can choose calendar icons, fonts, colors and type: one, two or three months on the desktop. Through interactive desktop the program accepts clicks on dates, appointments and tasks. Printing calendar data is easy, in monthly view or as a list of appointments in a chosen date range. Built-in address book allows you to keep details about all your contacts and import them from other programs. CSV and iCal formats are supported for importing and exporting data. The program saves daily backup automatically.

(Source: http://download.cnet.com/Active-Desktop-Calendar/3000-2074_4-10020305.html)


You can set up a virtual machine to handle your requests the way you need. Use aforementioned software. Make dummy email somewhere and sign up for the FREE VERSION of AWS. There is a free version. If you're traffic exceeds a prescribed limit it will propose a bargain before charging, but you signed up with a Chime account and just move the money before Amazon gets any But for what you described the data is miniscule compared to hosting even a forum so if it makes sense to you give it a shot. You should never be charged.

  • Hello, this answer could focus more on the software recommendation part. E.g. which services from AWS do you recommend for this task? Also, how is AWS related to a virtual machine? Unless you mean "virtual" as in "online service", but "virtual machine" usually means something else.
    – Destroy666
    May 11, 2023 at 12:29

Mozilla Thunderbird now has in-built calendar support with all the needed functionality.

To store it locally, just choose On My Computer when creating a new one: Create calendar popup

Files can be synced between machines then as you mentioned.

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