How to Convert PST to ICS

Your calendar sits inside a PST file that only Outlook opens but Google Calendar, Apple Calendar and Thunderbird want ICS. Outlook's export wizard gives no ICS option so many users get stuck. Below are two ways to convert PST to ICS, with steps, limits and fixes for missing events.

What is an ICS file and why export a PST calendar?

An ICS file is a plain iCalendar file that stores events, dates, locations and reminders. Google Calendar, Apple Calendar, Thunderbird and most calendar apps open it. A PST file is Outlook's own container for mail, contacts and calendars so other apps cannot open it. Users export a PST calendar to move appointments to a new calendar app, share one calendar or retain a backup that any app opens. See ICalendar specification (RFC 5545) for format details.

How to convert PST to ICS with Outlook?

To export a PST calendar by hand, open your PST in Outlook, select its calendar and save it as iCalendar. Microsoft documents these steps for Outlook for Microsoft 365, Outlook 2024 and Outlook 2021. Its page does not include new Outlook so use classic Outlook for Windows.

1. Close Outlook, then restart it.
2. Go to File, Open & Export and select Open Outlook Data File. Browse to your PST and select it.
3. Switch to Calendar view and select your PST's calendar in your navigation pane.
4. Go to File and select Save Calendar.
5. Enter a file name. A summary shows your calendar name, date range and detail level.
6. Select More Options if you want to edit date range or detail level. A large date range creates a big file that takes time to save.
7. Select OK, then Save to save your ICS file.

Microsoft's page on how to Export an Outlook calendar to Google Calendar lists matching Save Calendar steps. Open your saved ICS file in any calendar app to confirm events look right. To open PST items outside Outlook first, see how to Fix a PST that is not an Outlook data file.

Why does Outlook fail for a PST calendar in bulk?

Outlook's Save Calendar suits one calendar and one small PST. It breaks down for bulk work because it needs Outlook installed, saves one selected calendar at a time and gives only date range and detail level for filtering. Microsoft also states that a saved file is a snapshot so later changes in Outlook never reach it.

Many users get stuck here. One Microsoft Q&A poster reported that Outlook's export wizard offered only OPML, CSV or PST while a new calendar needed an ICS file. That post shows that ICS comes from Save Calendar, not from wizard menus. See that original post, How do I export Outlook calendar to ICS file, on Microsoft Q&A. When you have many PST files or no Outlook, use a converter instead.

Steps to export a PST calendar with software

1. Install Corbett PST File Converter on your Windows PC with administrator rights.
2. Select Open, then Email Data Files, then Outlook PST Files and Choose from a Folder.
3. Browse to your PST file and select OK to open it.
4. Preview your PST data in its panel. Untick every folder except Calendar.
5. Set a date range filter if you want only some events.
6. Select Export and choose ICS as your saving format.
7. Browse to a save location and select Save to create your ICS files.

Copy your PST to a safe drive before you start so your original remains untouched. Test your PST to ICS output in free demo first, then open one ICS file in your calendar app. Lifetime licence starts at $99 with a 30-day money-back window. To build a PST from Maildir mail, see how to Convert Maildir to PST. For contact files, see how to Combine VCF files into one.

Which way suits your PST calendar?

Use Outlook's Save Calendar to export a PST calendar for one small calendar when Outlook is already installed. Use software to convert PST calendar to ICS when you have many files, no Outlook or a need for date filters.

How to import your ICS file after the export?

Open your new calendar app and use its import option to open your ICS file. In Google Calendar, open settings, select Import & export and upload your file. Apple Calendar and Thunderbird also open ICS files from their file menus. Microsoft notes that an exported file is a snapshot so changes in Outlook after the export never appear in your new calendar. Import once, then manage events in your new app.

Why are events missing after the export?

Missing events come from three causes. A narrow date range in Save Calendar leaves older events out so widen it under More Options. A calendar you did not select in Outlook never reaches your file so confirm your PST's calendar name before you save. Unticked folders and active filters exclude events in any tool.

Check date range first, then calendar selection, then filters when your PST to ICS file looks incomplete. Compare event counts in Outlook with your imported calendar. To open a damaged PST before you convert, see how to Fix a PST that is not an Outlook data file.

Questions About ICS Files