Outlook Split PST File by Year: How-To & Tools

Updated 7 November 2026 · Standard formula, shown below

Yes, you can split an Outlook PST file by year, and the most reliable method is to archive or export messages by date range into separate PST files. This article explains the built-in Outlook tools and third-party options, their limitations, and step-by-step instructions for both manual and automated approaches.

Why Split a PST File by Year?

Outlook PST files have a practical size limit of 50 GB (older versions 20 GB). As the file grows, Outlook becomes slower, more prone to corruption, and may fail to open. Splitting by year is a common strategy because it creates logical, manageable chunks—each year’s email is separate, making backups, searches, and transfers easier. For example, a user with 10 years of email can create 10 smaller PST files, each containing one year of data.

Built-In Methods: Archive and Export

Outlook offers two built-in features to move data out of a PST: AutoArchive and Export. Both can filter by date, but they work differently.

AutoArchive (or Online Archive in newer versions) moves items older than a specified date to a separate PST. It can be configured per folder, but it doesn’t let you choose a specific year—only “older than X days.”
Export to a file (File > Open & Export > Import/Export) allows you to specify a date range in the filter. This is the most direct way to split by year.

For a clean yearly split, the Export method is preferred because you control the exact date range.

Step-by-Step: Export a Single Year to a New PST

Follow these steps to create a PST containing only emails from a specific year (e.g., 2022).

In Outlook, go to File > Open & Export > Import/Export.
Choose Export to a file and click Next.
Select Outlook Data File (.pst) and click Next.
Select the folder you want to export (e.g., Inbox) or the entire mailbox. Check Include subfolders if needed.
Click Filter to open the filter dialog.
Go to the Advanced tab. Click Field > Date/Time fields > Received.
Set the condition to between and enter 1/1/2022 and 12/31/2022 (or your year). Click Add to List, then OK.
Click Next, choose a destination for the new PST, and set a password if desired.
Finish the wizard. Outlook will create the new PST and copy matching items.

Repeat for each year you want to split. Note that this copies items; the original remains in the source PST. To reduce the original size, you must delete the copied items after verifying the new PST is intact.

Using AutoArchive for Yearly Splits

AutoArchive can approximate a yearly split by archiving items older than a certain number of days. For a calendar year, set the archive age to 365 days (or 366 for leap years). However, this does not give a precise “January 1 to December 31” boundary—it uses a rolling date. For example, if you run it on March 15, 2024, it archives everything before March 15, 2023, which cuts across two calendar years.

To get a clean year, you would need to run AutoArchive on January 1 of the following year, which is rarely practical. The Export method is more precise.

Third-Party Tools for Automated Splitting

Several third-party utilities can split PST files by year automatically. These tools often provide a GUI where you select the source PST, choose a split criterion (e.g., by year, by month, by size), and they create multiple output PSTs. They can also handle large files and preserve folder structure. Some popular options include Stellar Splitter for Outlook, SysTools PST Splitter, and Kernel for PST Split.

When using third-party tools, be aware of the following:

They are not free—most offer a trial with limited functionality (e.g., split only a few items).
They may not support the latest Outlook versions immediately.
Always back up your original PST before running any splitter.

Common Problems and How to Avoid Them

Splitting a PST by year can hit a few snags:

Date filter not working: Make sure you select the correct field (Received, not Sent) and use the Advanced tab. Some users mistakenly apply a filter to the wrong folder.
Duplicate items: Export copies, so after splitting you may have duplicates if you don’t delete the originals. Use Outlook’s Clean Up tools or manually delete after verification.
Large PST corruption: If your PST is already near the size limit, the export may fail. Run Scanpst.exe (Inbox Repair Tool) before attempting the split.
Missing subfolders: If you don’t check “Include subfolders,” you’ll miss emails in nested folders. Always check it unless you deliberately want only one folder.

How to Choose the Right Method

Your choice depends on your needs:

One-time split: Use the built-in Export with a date filter. It’s free and works well for a single year.
Recurring splits (e.g., every year): Set up AutoArchive with a yearly schedule, but accept the rolling-date limitation. Or use a third-party tool that supports scheduled splits.
Very large PST (>50 GB): Third-party tools are often more efficient because they can split without loading the entire file into memory, reducing the risk of crashes.

Frequently Asked Questions

Q: Can I split a PST file by year without losing any emails?
Yes, if you use the Export method, it copies items, so nothing is lost. After verifying the new PST, you can delete the originals to reduce size. Always keep a backup until you’re sure.

Q: Does splitting a PST by year affect my Outlook performance?
Yes, positively. Smaller PST files load faster and are less prone to corruption. Outlook will run more smoothly overall.

Q: Can I merge the yearly PST files back later?
Yes, you can use Outlook’s Import/Export to merge them, or open each PST and drag items into a single folder. However, merging can create duplicates, so use a deduplication tool if needed.

Q: Is there a way to split a PST by year for free?
The built-in Export method is free. It’s manual but works. Third-party tools are not free, but some offer free trials that may allow splitting a limited number of items.

Q: What is the maximum size for a PST file in Outlook 2016 and newer?
The default limit is 50 GB, but this can be increased via registry settings. However, Microsoft recommends staying below 50 GB for performance. Splitting by year helps you stay well under that.

Q: Will splitting by year break my email rules or search folders?
Rules are stored in the mailbox, not in the PST, so they remain intact. Search folders may need to be recreated because they are based on the original PST. After splitting, you can create new search folders in each yearly PST.

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.