Quick answer
- Outlook way: open your PST in classic Outlook, select its calendar, then go to File and Save Calendar to convert PST to ICS.
- Limit: Save Calendar needs Outlook installed and saves one selected calendar at a time. Its file is a snapshot, so later changes do not update it.
- Software way: desktop software loads your PST without Outlook, lets you select your calendar folder and date filters, then exports PST calendar 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 offers 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 convert PST to ICS?
An ICS file is a plain iCalendar file that stores events, dates, locations and reminders. Google Calendar, Apple Calendar, Thunderbird and most calendar apps read it. A PST file is Outlook's own container for mail, contacts and calendars, so other apps cannot open it. Users convert PST to ICS to move appointments to a new calendar app, share one calendar or keep a backup that any app opens. See iCalendar specification (RFC 5545) for format details.
How to convert PST to ICS with Outlook?
To convert PST to ICS 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 cover new Outlook, so use classic Outlook for Windows.
- Close Outlook, then restart it.
- Go to File, Open & Export and select Open Outlook Data File. Browse to your PST and select it.
- Switch to Calendar view and select your PST's calendar in your navigation pane.
- Go to File and select Save Calendar.
- Enter a file name. A summary shows your calendar name, date range and detail level.
- Select More Options if you want to change date range or detail level. A very large date range creates a big file that takes time to save.
- Select OK, then Save to write 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, read how to fix a PST that is not an Outlook data file.
Why does Outlook fail to convert PST to ICS 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 offers 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. Read 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.
How to convert PST to ICS in bulk with software?
Use Corbett PST File Converter to convert PST to ICS without Outlook. Its page says contacts convert to vCard and calendars convert to ICS, with no file size limit and no Outlook install. Filters cover date range, time range and sender fields, so you save only matched items.
Steps to convert PST to ICS with software
- Install Corbett PST File Converter on your Windows PC with administrator rights.
- Select Open, then Email Data Files, then Outlook PST Files and Choose from a Folder.
- Browse to your PST file and select OK to load it.
- Preview your PST data in its panel. Untick every folder except Calendar.
- Set a date range filter if you want only some events.
- Select Export and choose ICS as your saving format.
- 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 stays 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, read how to convert Maildir to PST. For contact files, see how to combine VCF files into one.
Which way to convert PST to ICS is best?
Use Outlook's Save Calendar to convert PST to ICS 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.
| Way to convert PST to ICS | Cost | Needs | Filters | Best for |
|---|---|---|---|---|
| Outlook Save Calendar | Free | Classic Outlook, your PST | Date range, detail level | One small calendar |
| Corbett PST File Converter | Free demo, then from $99 | Windows PC, your PST | Date, time, sender fields, file size | Many PST files or no Outlook |
How to import your ICS file after you convert PST to ICS?
Open your new calendar app and use its import option to load 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 you convert PST to ICS never appear in your new calendar. Import once, then manage events in your new app.
Why are events missing after you convert PST to ICS?
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 leave events behind 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, read how to fix a PST that is not an Outlook data file.
Key takeaways
- To convert PST to ICS in Outlook, open your PST, select its calendar, then use File and Save Calendar.
- Outlook's export wizard offers no ICS option, so Save Calendar is your manual route.
- An exported ICS file is a snapshot. Later Outlook changes never update it.
- Corbett PST File Converter converts PST calendars to ICS without Outlook, with date filters and no file size limit.
- To convert PST to ICS with confidence, compare event counts in Outlook with your imported calendar.
Questions about PST to ICS
How do I convert PST to ICS?
Open your PST in classic Outlook, select its calendar and use File and Save Calendar, or use software to convert PST to ICS without Outlook.
Can I convert a PST calendar to ICS without Outlook?
Yes. Corbett PST File Converter loads your PST without Outlook and exports calendars to ICS.
Does Outlook's export wizard create ICS files?
No. Its wizard offers PST, CSV and OPML. Use Save Calendar to create ICS.
Does Save Calendar work in new Outlook?
Microsoft's steps cover Outlook for Microsoft 365, 2024 and 2021 and do not mention new Outlook. Use classic Outlook for Windows.
Can I convert PST to ICS for free?
Yes. Outlook Save Calendar costs nothing. Software adds batch conversion and filters.
Does an ICS file update when my calendar changes?
No. Microsoft states that an exported file is a snapshot of your calendar.
Which apps open an ICS file?
Google Calendar, Apple Calendar, Thunderbird and most calendar apps open ICS files.
Can I convert contacts from a PST too?
Yes. Corbett's page says contacts convert to vCard while calendars convert to ICS.
Is there a file size limit for PST to ICS software?
No. Corbett's page says no file size limit applies.
Should I back up my PST before I convert it?
Yes. Close Outlook and copy your PST to a safe drive, so your original stays untouched.
