Export Outlook Calendar to ICS
Export Microsoft Outlook calendar to ICS format with timezone fixes. Works with Outlook desktop, web, and Microsoft 365. Fix Windows timezone identifiers for Google Calendar and Apple Calendar compatibility.
Export Outlook Calendar to ICS – Desktop, Web, and Microsoft 365
Microsoft Outlook stores calendar data in proprietary formats such as PST (Personal Storage Table) and OST (Offline Storage Table) files. While these formats work well within the Outlook ecosystem, they are not directly compatible with other calendar applications like Google Calendar, Apple Calendar, or Thunderbird. Exporting your Outlook calendar to the ICS (iCalendar) format creates a universally compatible file that can be imported into virtually any scheduling tool. This guide and tool help you produce a clean, standards-compliant ICS export from Outlook, whether you use the desktop application, Outlook on the web, or Microsoft 365.
How to Export a Calendar from Outlook Desktop
In Outlook for Windows, navigate to the Calendar view and select the calendar you want to export in the folder pane. Click File, then Save Calendar. In the dialog box, choose a location and filename, then click More Options to set the date range and detail level. Selecting "Full details" ensures that event descriptions, attendee lists, and attachments are included. Click OK, then Save. The resulting .ics file contains all events within the specified range. On macOS, Outlook does not offer a direct ICS export, but you can drag events to the desktop to create individual .ics files or use this tool to convert an exported OLM file. For Outlook on the web, open Settings, then View all Outlook settings, then Calendar, then Shared calendars, and use the Publish a calendar option to obtain an ICS link you can download.
Limitations of the Built-In Outlook Export and How This Tool Helps
Outlook native ICS export has several known limitations. The Windows desktop version uses Windows timezone identifiers instead of IANA identifiers, which causes time shifts when the file is imported into Google Calendar or Apple Calendar. The detail level selector sometimes omits attendee information or strips HTML formatting from descriptions. Recurring events may lose certain exception details depending on the Outlook version. This tool addresses these issues by post-processing the exported ICS file: it converts timezone identifiers, restores proper text escaping, normalizes recurrence rules, and adds any missing VTIMEZONE definitions. The result is an ICS file that other calendar applications can import without timezone errors or data loss.
Exporting Shared and Delegated Outlook Calendars
In a corporate Microsoft 365 environment, you may have access to shared team calendars or delegated calendars from colleagues. Exporting these requires the appropriate permissions. If you have editor or owner access to a shared calendar, you can open it in Outlook desktop, switch to that calendar, and follow the same File, then Save Calendar workflow. For delegated calendars, the process is identical once the calendar is added to your Outlook profile. Administrators can also use PowerShell and the Exchange Web Services API to programmatically export calendars for multiple users, which is useful during migrations. After export, run each file through this tool to ensure cross-platform compatibility before distributing the ICS files to end users.
Migrating from Outlook to Google Calendar or Apple Calendar
If you are switching away from Outlook entirely, the ICS export is the cleanest migration path. Export your Outlook calendar as described above, process the file with this tool to fix timezone and formatting issues, and then import the optimized ICS file into your new calendar application. Google Calendar accepts ICS imports through its web interface under Settings, then Import and Export. Apple Calendar on macOS lets you import by double-clicking the .ics file or using File, then Import. For calendars with more than a few thousand events, consider splitting the file into smaller batches to avoid import timeouts. After migration, verify that recurring events, reminders, and all-day events transferred correctly by spot-checking a sample of entries in the new calendar.
Preserving Outlook-Specific Properties in the ICS File
Outlook uses several proprietary properties prefixed with X-MICROSOFT to store data like event color categories, sensitivity levels, and meeting response status. Standard calendar applications ignore these properties, but they can be useful if you plan to re-import the file into Outlook later. This tool preserves X-MICROSOFT properties in the output file rather than stripping them. This means you retain the full richness of the Outlook data while also having a file that works everywhere else. If you prefer a leaner file without Outlook-specific extensions, you can choose to strip custom properties during processing.
Frequently Asked Questions
Can I export my Outlook calendar without the desktop application?
Yes. Outlook on the web allows you to publish a calendar and obtain an ICS download link. Go to Settings, then Calendar, then Shared calendars, and use the Publish option. You can then download the ICS file from the generated URL.
Why do my events show the wrong time after exporting from Outlook?
Outlook uses Windows timezone identifiers in its ICS exports, which are not recognized by many other calendar applications. This tool converts those identifiers to the IANA standard, ensuring events appear at the correct time after import.
Does the export include recurring events?
Yes. When you export from Outlook with full details, recurring events are included with their recurrence rules. This tool normalizes the RRULE format to ensure maximum compatibility with Google Calendar, Apple Calendar, and other applications.
Can I export only events within a specific date range?
When using Outlook desktop, the Save Calendar dialog includes a date range selector. You can specify the start and end dates to limit the export. This is useful for archiving past events or exporting only upcoming meetings.
What about event attachments in the ICS file?
Outlook can include attachments in the ICS export, but the behavior varies by version. Desktop Outlook may embed small attachments as base64-encoded data. Large attachments are often excluded. Check the detail level settings when exporting.
Is this tool useful for IT administrators managing calendar migrations?
Yes. Administrators migrating users from Exchange or Microsoft 365 to another platform can use this tool to batch-process ICS exports, fixing timezone and formatting issues before distributing files to end users or importing them into the target system.
Will the exported file work with Thunderbird?
Yes. After processing with this tool, the ICS file conforms to RFC 5545 and can be imported directly into Thunderbird by going to Events and Tasks, then Import. Thunderbird handles the standard ICS format natively.