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PST to MBOX Converter

Combine Outlook PST files into one MBOX mailbox for import into Thunderbird, Apple Mail or other clients.

Your files never leave your device

How to convert PST to MBOX

  1. 1

    Choose your PST file

    Click the upload area or drag files onto it. Nothing is uploaded — files are opened locally.

  2. 2

    Start the conversion

    Press the convert button. Your browser converts the files in seconds.

  3. 3

    Download the result

    Save each file individually or everything at once as a ZIP.

Merge many individual messages from Outlook for Windows exports and archives into a single MBOX file — the easiest way to import a batch of emails into Thunderbird or Apple Mail, or to archive them as one file.

Read the full guide with screenshots

What is PST?

PST (Personal Storage Table) is the file Outlook for Windows uses to store and archive email, contacts and calendars. Exports and backups from Outlook are usually PST files.

What is MBOX?

MBOX stores a whole mailbox — thousands of emails — in one file. Google Takeout, Thunderbird and Apple Mail exports all use it.

Is it private?

Yes. Unlike upload-based converters, ZapMorph processes files inside your browser tab, so the file stays on your device. It is never transmitted, stored or logged — close the tab and it’s gone.

Frequently asked questions

Is the pst to mbox converter free?

Yes. Convert 1 file a day without an account, or 5 files a day with a free account. Pro removes all daily limits.

Are my files uploaded to a server?

No. The conversion runs entirely in your browser, so your files never leave your device. We only count how many files you convert — never their names or contents.

What is the maximum file size?

Up to 25 MB per file without an account, 50 MB with a free account, and 1 GB on Pro. Very large files also depend on your device’s memory.

Can I convert multiple PST files at once?

PST to MBOX Converter works on one file at a time and can produce many output files, which you can download together as a ZIP.

Does it work on Mac, Windows, iPhone and Android?

Yes. It works in any modern browser — Chrome, Edge, Firefox and Safari — on desktop and mobile, with nothing to install.

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