Convert MBOX to PDF online (Google Takeout, Thunderbird)

MBOX to PDF works one message at a time: drop the .mbox file, pick a message from the list and press Save as PDF. Each PDF has the headers, body, inline images and the attachment list, and the attachments download as original files. The mailbox is read inside your browser tab; nothing is uploaded.

What is inside an MBOX file and where you get one

An .mbox file is one long text file with many emails stacked one after another, each starting with a "From " line. Google Takeout exports your whole Gmail (or selected labels) this way; Thunderbird stores every folder as an mbox; Apple Mail's Export Mailbox writes one too. The format is open, so a browser can split it into messages without any mail client.

Takeout is the usual source: in Google Takeout select only Mail, pick labels if you want a subset, and download the archive. The steps are on backing up Gmail emails; the format itself is explained in the MBOX file explainer.

How to convert MBOX to PDF

1. Unzip the Takeout archive and find the .mbox file inside the Mail folder. Thunderbird mbox files have no extension; you can rename them to .mbox or drop them as they are.
2. Drop the file on this page. A list of messages appears on the left with subject, sender and date.
3. Click a message. It renders on the right with the header block, body, inline images and attachments.
4. Press Save as PDF. The browser's print dialog opens; choose Save as PDF, set paper size and margins, save.
5. Repeat for the next message. The list stays open; click the next one and save again. Download attachments from each message's list, singly or as a ZIP.

What each PDF keeps

Every PDF starts with From, To, Cc, Date, Subject and Message-ID. The Message-ID matters for a mailbox export: it is the one field that identifies a message across copies, so a PDF with it can be matched back to the Takeout file or the live Gmail account. Inline images are resolved from the message; the body is rendered HTML or plain text, with a real text layer.

Page size and margins are chosen in the print dialog, not by the page. Attachments are listed with names and sizes and are downloaded as original files rather than printed. Compact mode hides quoted replies and signatures, which matters in Gmail threads where every reply quotes the whole history.

Large mailboxes: what to expect

The practical limit is browser memory. MBOX files of a few hundred megabytes open; listing thousands of messages takes a few seconds rather than being instant. Only the message you click is rendered, so scrolling the list is light.

Export is one PDF per message, produced by pressing Save as PDF again for each one. There is no merged, multi-message PDF yet, and no folder-wide "save all" button. For a handful of messages from a large Takeout this is quick; for an entire mailbox of thousands, a desktop converter that writes PDFs in bulk is the better fit.

MBOX to PDF: three ways compared

If you just need to read the mailbox and pull out a few records, start here. The open MBOX file guide covers Thunderbird and Apple Mail imports in more detail.

Want the mailbox back in Gmail instead of PDFs?

Many searches for an "mbox to gmail converter" come from people who exported a mailbox and now want it inside a Gmail account again. That is an import, not a conversion, and Gmail accepts it only over IMAP from a mail client. The route is Thunderbird with the Gmail account added, then drag the imported messages into a Gmail folder; it is free and keeps the original dates.

The full procedure, including what Takeout cannot do and the Apple Mail alternative, is on import MBOX to Gmail. Before importing, it is worth opening the MBOX here to check that the messages you expect are actually inside.

Frequently asked questions