100% Private & Secure

Free EML Converter
Convert to Any Format

Convert EML to PDF, MBOX, HTML, CSV, TXT, or JSON. Single or batch — private and secure.

6 output formatsBatch processingPreserves attachmentsInstant conversion

Drop EML files here

or click to browse · select multiple files

Overview

What Is EML to MBOX Conversion?

EML is the standard format for a single email message (RFC 822 and MIME). One .eml file holds one message. MBOX stores many messages in one file with From_ line separators. EML to MBOX conversion combines your EML messages into a single mailbox file you can open in Thunderbird, Apple Mail, or other MBOX clients.

This tool reads each EML file on your device, parses headers and body, and writes one MBOX file. No data is uploaded. You download a single .mbox file. Batch mode combines many EML files into one MBOX for import into your mail client.

Converting EML to MBOX is useful for migrating from multiple EML files to Thunderbird or Apple Mail, or for archiving many messages in one file. The process is free, private, and works with EML from any source.

All processing is private; nothing is sent to our servers. Your email files stay on your device until you download the MBOX.

Features

Features

Why use the EML to MBOX converter

Single MBOX mailbox

Convert one or more EML files into one MBOX file. Open it in Thunderbird, Apple Mail, or any MBOX-compatible client.

Batch EML to one MBOX

Drop multiple .eml files. All messages are concatenated into one .mbox file with proper separators.

RFC 4155 MBOX format

Output follows the MBOX format (e.g. mboxo) so mail clients can open and index messages correctly.

No upload

Conversion runs on your device. Your EML files stay on your device — nothing is sent to our servers.

Private & secure

Your email files never leave your device. Ideal for migrating EML into Thunderbird or Apple Mail.

How it works

How to Convert EML to MBOX

Four steps — no install, no sign-up

01
01

Open the EML to MBOX Converter

Come to this page — MBOX is already selected as the output format.

02
02

Drop one or more .eml files

Drag and drop .eml file(s) or click to browse. Multiple files are combined into one MBOX.

03
03

Review the email list

Check the preview table (From, To, Subject, Date). Ensure MBOX is selected as the output format.

04
04

Convert & download MBOX

Click Convert & Download. A single .mbox file is generated; open it in Thunderbird or Apple Mail.

FAQ

Frequently Asked Questions

Common questions about EML to MBOX conversion

Q1. What is EML to MBOX conversion?
EML to MBOX means turning one or more .eml email files into a single MBOX mailbox file. MBOX is a format that stores many messages in one file (with From_ separators). Thunderbird, Apple Mail, and other clients can open MBOX directly.
Q2. Why convert EML to MBOX?
MBOX is useful when you want one mailbox file instead of many .eml files. Use it to import into Thunderbird or Apple Mail, or to archive multiple EML messages in a single file.
Q3. Do you upload my EML files?
No. The converter processes entirely on your device. Your EML files are read and converted on your device; nothing is sent to our servers.
Q4. Can I convert multiple EML files to one MBOX?
Yes. Select or drop multiple .eml files. All are parsed and concatenated into one .mbox file with proper message separators.
Q5. Which mail clients support MBOX?
Thunderbird, Apple Mail, and many other email clients can open MBOX files. You can import the downloaded .mbox file into your client.
Q6. Is the EML to MBOX converter free?
Yes. The tool is free to use with no sign-up. There is no file size limit other than what your device can handle.
Related

Related Tools

More converters and viewers from OnlinePCTools

EML ConverterEML to PDFEML to MBOXEML to CSVEML to HTMLEML to TXTEML to JSONMBOX ConverterEML Viewer