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EML Batch Merge
Combine Multiple EML Files into MBOX

Upload multiple .eml files and merge them into a single MBOX archive. Reorder files, preview details, and download instantly. Everything runs on your device — your emails stay completely private.

Mail formats: MSG, PST, MBOX, NSF, EMLX, Office 365Document formats: HTML, PDF, MHT, TXT, CSVAuto-load EML & EMLXSelective conversion & date range filterHeaders preserved; attachments, notes, to-do supported

Drop your .eml or .emlx files here

or click to browse (select multiple)

Get Started with EML Merge in 3 Simple Steps

1
EMLMBOX

1. Upload EML files

Add one or more .eml email files to merge into one.

2
1
2
3

2. Arrange order

Reorder emails if needed. Optionally set output format.

3
Download

3. Download merged file

Download the merged EML or MBOX file.

Overview

What Is EML Batch Merge?

EML Batch Merge converts and combines multiple .eml and .emlx email files into mail formats (MSG, PST, MBOX, NSF, EMLX, Office 365) or document formats (HTML, PDF, MHT, TXT, CSV). The tool automatically scans and loads EML and EMLX files; message headers are not changed after conversion.

Use selective conversion from the preview section to include only the emails you need, or apply a date range filter. Full EML content is preserved — attachments, notes, to-do items, and metadata — so you get complete, compliant output.

Our tool reads each file on your device, preserves headers and body, and outputs standards-compliant MBOX (or other chosen format) ready for import into Thunderbird, Apple Mail, Outlook, or other clients.

Works with EML/EMLX from Microsoft Outlook, Mozilla Thunderbird, Apple Mail, Gmail (Google Takeout), and any client that saves in standard MIME format. All processing is local; nothing is uploaded to any server.

Features

Discover Features

Mail & document export, auto-scan EML/EMLX, selective conversion, date filter, and complete privacy — all on your device

Convert & Save in Mail Formats

Export EML files to MSG, PST, MBOX, NSF, EMLX, and Office 365–compatible formats. One tool for migration to Outlook, Thunderbird, Apple Mail, Lotus Notes, or cloud mailboxes.

Export in Document Formats

Save multiple EML files as HTML, PDF, MHT, TXT, or CSV. Create readable reports, archives, or spreadsheets for legal, compliance, or analysis without changing message content.

Auto-Scan EML & EMLX

The tool automatically detects and loads both .eml and .emlx files. Drop a folder or select multiple files — EML and EMLX are scanned and parsed in one batch.

Message Headers Preserved

Email message headers (From, To, Date, Subject, etc.) are never altered during conversion. Output files retain original metadata for compliance and archiving.

Selective Conversion from Preview

Choose which EML files to include from the preview table. Select or deselect individual messages before merging or exporting — only selected items are converted.

Date Range Filter

Filter by date range to convert only emails within a specific period. Set From and To dates to include just the messages you need for migration or discovery.

Attachments, Notes & To-Do

Full EML content is preserved: attachments, notes, to-do items, and inline content are kept in the output. No data loss when converting to MBOX or other supported formats.

Drag-to-Reorder

Rearrange the order of your EML files by dragging them in the file list. The final output respects your chosen order — useful for organizing emails chronologically or by topic.

Privacy-First

All EML files are read and merged entirely on your device. Nothing is sent to any server. Close the tab and nothing remains — your emails stay completely private and confidential.

Instant Results

Merging and conversion happen in milliseconds, even for hundreds of files. No waiting, no email, no account required. Drop your files and get downloadable output immediately.

How to Merge

Four steps: upload, reorder, merge, and download

01
01

Upload .eml or .emlx files

Drag and drop multiple .eml or .emlx files, or click to browse. The tool automatically scans and loads both formats. All files are read locally.

02
02

Review, reorder & select

See a preview table with subject, sender, date, and size. Reorder by drag-and-drop. Use checkboxes to select which emails to convert, or set a date range filter.

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03

Choose output format & merge

Pick output format: MBOX, MSG, PST, NSF, EMLX, Office 365, or document (HTML, PDF, MHT, TXT, CSV). Click Merge/Convert — message headers and attachments are preserved.

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04

Download result

Download the merged mail file (e.g. MBOX, PST) or document export (HTML, TXT, CSV). Processing is instant and stays on your device.

Use Cases

Common scenarios where merging EML files into MBOX saves time

Email Archival

Consolidate scattered .eml files exported from Outlook, Thunderbird, or Gmail into a single MBOX archive for long-term storage, compliance, or backup purposes.

Legal Discovery

Combine relevant emails from a case or investigation into a single file for review. The MBOX format preserves headers and metadata needed for legal proceedings.

Mail Client Migration

Moving from one email client to another? Merge individual EML exports into MBOX format that most mail clients can import directly, preserving all messages and headers.

Email Analysis

Merge related emails into one file for importing into analysis tools. Researchers and analysts can process a single MBOX rather than handling hundreds of individual files.

Team Collaboration

Collect email threads from team members as individual .eml files, then merge them into a single archive that everyone can reference. Simpler than forwarding long chains.

Backup & Deduplication

Combine multiple email export folders into unified MBOX archives. Reduces file clutter and makes it easier to search, share, or import email collections into new systems.

Compare Plans

Free vs Paid — EML Merge

Get started free, upgrade when you need more power.

Feature
Free
Paid
Daily usage
5 uses/day
Unlimited
File size limit
50 MB
200 MB (1 GB for All Tools)
All core features
No software installation
Works on any device
Files stay on your device
Batch processing
Priority support
Upgrade — starting at $24.99/mo
Upgrade to Full Version

Unlock the Full Power of EML Merge

Remove daily limits, process larger files up to 1 GB, enable batch processing, and get priority support.

Buy Full Version — $24.99/moor $1,000/yr enterprise

All Tools Bundle includes:

  • All 60+ tools & 21 viewers included
  • Unlimited daily uses
  • 1 GB file size limit
  • All advanced features
  • Batch processing
  • All export formats
  • Priority email support
FAQ

FAQ

Frequently asked questions about the EML Batch Merge tool

Q1. What output formats are supported?
You can convert EML files and save in mail formats (MSG, PST, MBOX, NSF, EMLX, Office 365) or export in document formats (HTML, PDF, MHT, TXT, CSV). MBOX and TXT are available in-browser; other formats may be available in the full version.
Q2. Does the tool support EMLX files?
Yes. The tool automatically scans and loads both .eml and .emlx files. Drop a mix of EML and EMLX (e.g. from Apple Mail) and they are all parsed and listed in the preview. You can then merge or export in your chosen format.
Q3. Are message headers changed after conversion?
No. Email message headers (From, To, Date, Subject, Cc, Bcc, etc.) are preserved exactly. The tool does not alter headers — only combines or converts the messages into the output format you choose.
Q4. Can I select only some emails to convert?
Yes. In the preview section you can select or deselect individual EML files via checkboxes. Only selected messages are included when you merge or export. You can also use the date range filter to include only emails within a From/To date range.
Q5. Is there a date range filter?
Yes. Set a From and To date to filter which emails are included in the conversion. Only messages whose Date header falls within that range are merged or exported. Useful for legal discovery or migrating a specific time period.
Q6. Does it support EML files with attachments, notes, and to-do?
Yes. Full EML content is preserved: attachments, notes, to-do items, and inline MIME content are kept in the output. No data is stripped when converting to MBOX or other supported formats.
Q7. What is an EML file?
An EML file is a single email message saved in MIME format (RFC 822). Most email clients — Outlook, Thunderbird, Apple Mail, Gmail — can export individual messages as .eml files. Each file contains the full email including headers, body text, and any attachments encoded inline.
Q8. What is MBOX format?
MBOX is a standard file format for storing a collection of email messages in a single text file. Each message is separated by a 'From ' line (with a space after 'From'). It's widely supported by Thunderbird, Apple Mail, mutt, and many email archiving tools.
Q9. Is my email data safe?
Yes. All files are read and merged entirely on your device using browser APIs. Nothing is uploaded to any server. We have zero access to your email content — close the tab and nothing remains.
Q10. Can I open the MBOX file in Thunderbird?
Yes. Thunderbird natively supports MBOX files. You can use the ImportExportTools NG add-on to import MBOX files directly, or place the file in your Thunderbird profile's Mail directory. Apple Mail also supports MBOX import via File > Import Mailboxes.
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