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EML MBOX

Convert EML to MBOX
Online Tool

Convert EML files to MBOX format online. Free tool, EU servers, GDPR compliant, auto-delete 24h. No software to install.

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🛡️ GDPR Compliant 🔒 TLS 1.3 Encryption 🇪🇺 Hosted in EU 🇫🇷 Built in France 🗑️ Auto-delete 24h

What is a EML file?

EML (Email Message) is the file format used by Windows Mail, Thunderbird, most clients. It stores email messages along with their metadata, attachments, and folder structure.

EML files are commonly encountered when:
- Migrating between email platforms — switching from Windows Mail, Thunderbird, most clients to another system
- Email archiving — long-term storage of email communications
- Legal and compliance — eDiscovery and regulatory requirements
- Backup and recovery — protecting email data from loss

While EML is widely used in its native ecosystem, working with these files outside of Windows Mail, Thunderbird, most clients can be challenging without proper conversion tools.

What is a MBOX file?

MBOX (Mailbox) is the format used by Thunderbird, Gmail, Unix mail. It provides a structured way to store and organize email messages with full support for attachments, metadata, and folder hierarchies.

MBOX is the preferred format for:
- Thunderbird, Gmail, Unix mail — native file format for import and export
- Cross-platform compatibility — supported on Any OS (cross-platform)
- Email archiving — reliable long-term storage
- Data migration — widely accepted by email migration tools

By converting to MBOX, your emails become accessible in Thunderbird, Gmail, Unix mail and compatible email applications.

Why convert EML to MBOX?

Converting EML to MBOX is essential in several scenarios:

1. Migrating to Thunderbird, Gmail, Unix mail
If you're moving to Thunderbird, Gmail, Unix mail, converting EML to MBOX allows you to import your entire email archive with folder structure and metadata preserved.

2. Cross-platform access
EML files require Windows Mail, Thunderbird, most clients to open natively. Converting to MBOX makes your emails accessible on Any OS (cross-platform).

3. Email archiving and compliance
Organizations often need to convert email archives between formats for legal discovery, compliance requirements, or long-term storage strategies.

4. Opening emails without Windows Mail, Thunderbird, most clients
If you receive a EML file but don't have Windows Mail, Thunderbird, most clients, converting to MBOX lets you access the emails in Thunderbird, Gmail, Unix mail or any compatible client.

EML vs MBOX — Key Differences

Feature EML MBOX
Ecosystem Universal (most email clients) Universal (Thunderbird, Gmail, Apple Mail...)
File structure Plain text (RFC 5322 MIME) Plain text, emails concatenated
Openness Open standard (RFC 5322) Open standard (RFC 4155)
Platform Any OS Any OS (cross-platform)
Data types Single email message Email only
Free readers Most email clients Many free clients available

3 methods to convert EML to MBOX

Method 1: Manual conversion via email client

Import the EML file into a compatible email client, then export in MBOX format. This requires having both source and target applications installed.

Pros

  • ✓ Free if you already have the software
  • ✓ Full control over the process

Cons

  • ✗ Requires specific software installed
  • ✗ Multi-step manual process
  • ✗ Time-consuming for large files
  • ✗ Risk of data loss during manual steps

Method 2: Desktop conversion software

Several desktop converters can handle the EML to MBOX conversion locally. These paid tools typically cost between $29 and $99 per license.

Pros

  • ✓ Direct conversion
  • ✓ Works offline

Cons

  • ✗ Paid ($29-$99)
  • ✗ Windows only
  • ✗ Installation required
  • ✗ Limited file size support
Recommended

Method 3: MailtoPst (online, free trial)

Upload your EML file to MailtoPst, select MBOX as the output, and download. Works from any browser, no software needed.

Pros

  • ✓ First conversion free
  • ✓ No Windows Mail, Thunderbird, most clients needed
  • ✓ Works on Mac, Linux, Windows
  • ✓ Preserves folder structure
  • ✓ GDPR compliant, EU servers

Cons

  • ✗ Requires internet connection
  • ✗ Paid after first conversion
Try MailtoPst →

Step by step

How to convert EML to MBOX with MailtoPst

01

Upload your EML file

Drag & drop or click to upload your .eml file. Files up to 51 GB supported with resumable upload.

02

Choose MBOX as output

Select MBOX from the format dropdown. MailtoPst auto-detects the best conversion settings.

03

Download your MBOX file

Conversion takes seconds. Download your .mbox file or receive it by email.

Convert your EML to MBOX now →

100 MB free credit. No credit card required.

FAQ

Frequently Asked Questions

Can I convert EML to MBOX without Windows Mail, Thunderbird, most clients?

Yes. MailtoPst reads EML files server-side — you don't need Windows Mail, Thunderbird, most clients installed. Just upload the file from any browser on any operating system.

Will my folder structure be preserved?

Yes. MailtoPst preserves the original folder hierarchy from your EML file when converting to MBOX.

Is EML to MBOX conversion free?

Your first conversion is free with no credit card required. Credit packs start from €4.99.

What about attachments and metadata?

MailtoPst preserves all attachments, email headers, timestamps, read/unread status, and other metadata during the conversion.

How large can my EML file be?

MailtoPst supports files up to 50 GB with resumable upload technology. If your connection drops, you can resume where you left off.

Related conversions

EML → PST EMLX → PST MBOX → PST PST → EML PST → MBOX
See all 30 conversion paths →

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First conversion free. No credit card required.

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