EML Tools

Open an MBOX file online

This MBOX reader lists every email in a mailbox file, lets you search by subject or sender, and opens any message with its attachments. Drop the file on the box to view it.

Runs in your browser. Your files never leave your device.

How to use it

  1. Choose your .mbox file or drag it onto the box. Large Google Takeout exports are fine.
  2. Search or sort the list, then click an email to read it below. Arrow keys move through the list.
  3. Save any message as an .eml file or PDF, or download its attachments.

What is an MBOX file?

MBOX is a mailbox format that stores many emails one after another in a single file. Each message starts with a line beginning with “From ”, followed by its headers and body, so a whole folder of mail fits in one file.

Google Takeout exports Gmail as .mbox, Thunderbird keeps each folder as an mbox file, and Apple Mail uses the format when you export a mailbox.

How to open an MBOX file

Windows and macOS have nothing that opens an .mbox file with a double-click, and Outlook can't read the format at all. The usual advice is to install Thunderbird and import the mailbox, which takes a while for a large Gmail export.

Here you drop the file on the box and the list of emails appears within seconds, even for several gigabytes. Click a message to read it, with its formatting and attachments.

Where to find your MBOX file

Google Takeout: unzip the download and look in Takeout/Mail for files such as “All mail Including Spam and Trash.mbox”.

Thunderbird: each folder is a file without an extension, such as Inbox or Sent, inside the Mail or ImapMail folder of your Thunderbird profile. Drag it onto the box.

Apple Mail: Mailbox > Export Mailbox creates a folder whose name ends in .mbox. The emails are in the file called “mbox” inside it. If Finder shows the folder as a single item, right-click it and choose Show Package Contents.

FAQ

How large an MBOX file can it open?

Mailboxes of several gigabytes work. The file is read in chunks to build the list, and an email is only decoded when you open it, so the whole mailbox never has to be loaded at once.

Is my mailbox uploaded?

No. The file is read by your browser on your device and never sent anywhere. A Gmail export can hold years of personal mail, so that matters more here than anywhere.

Can I save a single email from an MBOX file?

Yes. Open the email and press “Save as .eml” for a standard email file, or “Save as PDF” to keep a printable copy. To convert many emails at once, use the MBOX converter.

Is there an MBOX reader for Windows or Mac?

You don't need to install one. This page reads .mbox files in any current browser on Windows, Mac or Linux.

Can Outlook open MBOX files?

No, Outlook can't open or import MBOX. Convert the emails to .msg with the MBOX converter and drag them into an Outlook folder, or save single messages as .eml here.

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