Import a PST file into Gmail (without Outlook)

The route

1. PST → MBOX: open the .pst in Letterlark, select a folder, and use Export → MBOX (see ../pst-to-mbox/).
2. MBOX → Thunderbird: install Thunderbird (free) and the ImportExportTools NG add-on, then import the .mbox file into Local Folders.
3. Thunderbird → Gmail: add your Gmail account to Thunderbird (it uses IMAP). Create a label/folder in the Gmail account and drag or copy the imported messages into it.
4. Wait for Thunderbird to finish uploading, then check the label in Gmail on the web.

Tips

• Do it folder by folder – it is easier to check and to resume if something stops.
• Very large uploads are slow, and Google may limit how fast mail can be added. Moving a big archive can take hours.
• If you use Google Workspace (a work or school account), your administrator may offer Google’s own Outlook migration tools, which need Outlook on Windows.

Why not upload the PST to an online converter?

You can. Many converters upload the file to their server, though, which means handing your entire mailbox to a third party – check how a site works before you use it. Letterlark does the PST to MBOX step on your own computer, and Thunderbird talks directly to Google.