How to convert MBOX to CSV?

Choose the .mbox file in the tool above and press Extract addresses. It reads the From, To and Cc headers of every message in your browser and gives a CSV with one row per address: name, message count, how often the address was a sender or recipient, and first and last seen dates.

How to extract emails from an MBOX file?

Parse each message's headers and collect the addresses, which this tool does without uploading the file. In Python, the standard mailbox.mbox class plus email.utils.getaddresses does the same thing if you'd rather script it.

How to extract email addresses from Gmail messages?

Export the messages as .mbox with Google Takeout (select Mail, and labels if you only want some), unzip the download and open the .mbox here. Every sender and recipient comes out in one CSV.

What is an MBOX file?

A plain-text mailbox format that stores many email messages one after another in a single file, each starting with a line that begins with "From ". Gmail's Takeout export, Thunderbird and Apple Mail use it.

Can I import an MBOX file into Gmail?

Not directly; Gmail has no mbox import. The usual route is to open the mbox in Thunderbird, connect your Gmail account there by IMAP, and copy the messages into a Gmail folder.

Do MBOX files contain attachments?

Yes. Attachments are stored inside the message text, encoded as base64, which is why mbox exports are large. This tool skips them; only headers are read.

MBOX to CSV: extract email addresses from a Gmail export

To convert MBOX to CSV, open the .mbox file from Google Takeout, Thunderbird or Apple Mail in this tool. It reads only the message headers, in your browser, and lists every From, To and Cc address with the most used name, how many messages each appears in and when, ready to download as a CSV.

Mailbox export (.mbox or .eml)

Choose an .mbox or .eml fileAny size: the file is read in pieces, never all at once

Your mail never leaves this browser tab. Nothing is uploaded; only the From, To, Cc and Date headers are read.

Your own addresses, to leave out (optional)

Skip no-reply and notification sendersOnly people you wrote to (Gmail “Sent” label)

SimpleAPI

Sample result

jane@acme.example appears in 42 messages, and you wrote to them.

Contact: jane@acme.example
Messages: 42
Last seen: 30 Sep 2026

What this means for you

Your past contacts become a list, with the people you actually wrote to marked.

Next step:Verify the cleaned list

Every From, To and Cc address with names
Message counts and first and last seen
Marks who you wrote to from Sent mail
Optional skip of automated senders

MBOX
Contacts
CSV

By SimpleVerifier Team · Last updated October 17, 2026 · Runs in your browser; nothing you paste is sent to us

How do I convert an MBOX file to CSV?

Export your mail as .mbox: Google Takeout for Gmail (choose Mail), or the ImportExportTools NG add-on in Thunderbird, or Mailbox › Export Mailbox in Apple Mail. Unzip the Takeout download first.
Choose the .mbox file above (several files or single .eml messages work too) and add your own addresses so they're left out.
Press Extract addresses. A multi-gigabyte export is read in pieces, with a progress counter, and nothing is uploaded.
Filter out no-reply senders, or keep only people you wrote to, then download the CSV with names, counts and first and last seen dates.

Example

You enter: A Gmail Takeout .mbox file of 1,240 messages, with your own addresses entered to leave them out.
You get: One CSV row per contact, for example jane@acme.example (Jane Doe) in 42 messages, written to 15 times by you, first seen 2023-02-11 and last seen 2026-09-30.
Limits: Read in pieces in your browser and never uploaded; there is no file size cap, and large exports take longer.

How do I convert MBOX to CSV?

Load the .mbox file into a converter that parses the headers of each message and writes one row per address; this page does that in your browser. An mbox file is plain text: every message starts with a line beginning From and the messages sit one after another, a layout documented in RFC 4155. Inside each message the From, To and Cc headers follow RFC 5322.

Most desktop converters write one CSV row per message (subject, sender, date, body). That is the right output for an archive, but for outreach you want one row per person. This tool counts each address once per message, keeps the name it appears with most often, and decodes encoded names such as =?UTF-8?B?...?= (RFC 2047) so accented names come out readable.

How do I extract email addresses from Gmail?

Export the mailbox with Google Takeout and run the .mbox file through this tool. In Google Takeout, deselect everything, select Mail, optionally pick specific labels, and create the export. Google emails a download link; the .zip holds a file such as All mail Including Spam and Trash.mbox.

Takeout keeps Gmail's labels in an X-Gmail-Labels header on each message, which this tool reads. Messages labelled Sent were written by you, so the "Only people you wrote to" filter gives the list of contacts you've actually corresponded with, which is a much warmer list than everyone who ever emailed you.

How do I extract emails from an MBOX file without uploading it?

Use a converter that runs locally; this one reads the file inside the browser tab with the File streaming API, so your mail never reaches a server. Only the header block of each message is parsed; bodies and attachments are skipped as they stream past, so memory use stays small however large the export is.

Online converters that ask you to upload an mbox are asking for a copy of your whole mailbox, attachments included. If you have to use one, read its retention policy first. Desktop tools and Python's built-in mailbox module are the other private routes.

Can I use this with Outlook?

Not with Outlook's own files: Outlook for Windows exports .pst and Outlook for Mac exports .olm, which are binary formats this tool doesn't read. To get addresses out of Outlook, export your contacts to CSV from Outlook directly, or open the mailbox in Thunderbird and export .mbox from there.

Single messages saved as .eml (from Outlook on the web, Apple Mail or Thunderbird) do work: choose several at once and they're combined into one list.

Is this better than a desktop MBOX converter?

	This tool	Desktop MBOX to CSV converters	Python mailbox module
Output	One row per address, with counts and dates	Usually one row per message	Whatever you script
Install	None	Windows or Mac app, often paid	Python
Where the mail goes	Stays in your browser	Stays on your computer	Stays on your computer
Large exports	Streamed, any size	Varies	Streams if you write it to

Who uses this tool, and for what?

Founders and consultants: Rebuild a contact list from years of Gmail before a launch or a new venture, keeping only people you actually wrote to.
Sales teams: Recover a departing rep's correspondents from a mailbox export, so accounts don't go dark.
Recruiters: Turn an old inbox into a list of candidates and hiring managers you've already been in touch with.
Agencies: Pull a client's past customer correspondents out of an archive for a re-engagement campaign, without uploading their mail anywhere.

What can’t this tool tell you?

It lists addresses that appear in headers. It can't tell you whether a mailbox still exists; old addresses are the likeliest to bounce.
Outlook .pst and .olm files aren't supported; export .mbox from Thunderbird or contacts as CSV from Outlook instead.
Bcc recipients only appear on messages you sent, and only when your mail client kept the Bcc header.
The no-reply filter is a pattern match on common automated addresses; review the CSV before you mail anyone.
Having someone's address in your inbox isn't consent to market to them. Check the rules that apply to you (CAN-SPAM, GDPR, PECR) before a campaign.

Common questions

How to convert MBOX to CSV?: Choose the .mbox file in the tool above and press Extract addresses. It reads the From, To and Cc headers of every message in your browser and gives a CSV with one row per address: name, message count, how often the address was a sender or recipient, and first and last seen dates.
How to extract emails from an MBOX file?: Parse each message's headers and collect the addresses, which this tool does without uploading the file. In Python, the standard mailbox.mbox class plus email.utils.getaddresses does the same thing if you'd rather script it.
How to extract email addresses from Gmail messages?: Export the messages as .mbox with Google Takeout (select Mail, and labels if you only want some), unzip the download and open the .mbox here. Every sender and recipient comes out in one CSV.
What is an MBOX file?: A plain-text mailbox format that stores many email messages one after another in a single file, each starting with a line that begins with "From ". Gmail's Takeout export, Thunderbird and Apple Mail use it.
Can I import an MBOX file into Gmail?: Not directly; Gmail has no mbox import. The usual route is to open the mbox in Thunderbird, connect your Gmail account there by IMAP, and copy the messages into a Gmail folder.
Do MBOX files contain attachments?: Yes. Attachments are stored inside the message text, encoded as base64, which is why mbox exports are large. This tool skips them; only headers are read.

Sources

A tidy list can still be full of dead addresses.

Extracting, deduplicating and syntax checks all work on the text of an address. None of them can tell whether the mailbox exists. Only the server that hosts it can answer that, through an SMTP check, and that is what the paid product does.

Upload the cleaned file as it is: CSVs up to 100,000 rows
A real SMTP mailbox check on every row, with catch-all detection
Small list? $9 one-time covers 2,500 emails, no subscription

Get started — $29.99/mo See the published limits first

One plan, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.