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.
Drop your .eml files here
or click to browse (select multiple)
What Is EML Batch Merge?
EML Batch Merge combines multiple individual .eml email files into a single MBOX archive. The EML format stores one email per file, which is great for portability but cumbersome when you need to manage hundreds of messages. MBOX consolidates them into one file that any major email client can import.
Common reasons to merge include archiving email threads, preparing legal discovery bundles, migrating between email clients, consolidating exports from different accounts, and reducing file clutter for backup storage.
Our tool reads each EML file on your device, extracts the From and Date headers to build proper MBOX separator lines, escapes any conflicting "From " lines in the message body, and concatenates everything into a standards-compliant MBOX file ready for import.
The tool works with EML files exported from Microsoft Outlook, Mozilla Thunderbird, Apple Mail, Gmail (via Google Takeout), and any other client that saves messages in standard MIME format. Attachments are preserved since the full EML content is included in the MBOX output.
Discover Features
Multi-file upload, drag-to-reorder, MBOX output, and complete privacy — all on your device
Multi-File EML Upload
Upload dozens or hundreds of .eml files at once via drag-and-drop or file picker. The tool accepts multiple files simultaneously and parses each one to extract sender, subject, and date metadata.
Drag-to-Reorder
Rearrange the order of your EML files by dragging them in the file list. The final MBOX output respects your chosen order — useful for organizing emails chronologically or by topic.
MBOX Format Output
Generates a properly formatted MBOX file with correct 'From ' separator lines, escaped body content, and blank-line delimiters between messages. Compatible with Thunderbird, Apple Mail, and other MBOX readers.
Preview Before Download
See a summary table of all merged emails showing file name, subject, sender, date, and size before downloading. Verify everything looks correct before saving the MBOX file.
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 happens in milliseconds, even for hundreds of files. No waiting, no email, no account required. Drop your .eml files and get a downloadable MBOX archive immediately.
How to Merge
Four steps: upload, reorder, merge, and download
Upload .eml files
Drag and drop multiple .eml files onto the upload area, or click to browse your device. Select as many files as you need — they are all read locally.
Review & reorder
See all uploaded files with their detected subject, sender, and date. Drag files to reorder them or remove any you don't want included in the merge.
Merge files
Click 'Merge Files' to combine all EML files into a single MBOX archive. A progress bar shows the merge status for large batches.
Download MBOX or TXT
Download the merged file as an MBOX archive (compatible with Thunderbird, Apple Mail, etc.) or as a plain TXT concatenation. The file downloads instantly.
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.
Free vs Paid — EML Merge
Get started free, upgrade when you need more power.
Unlock the Full Power of EML Merge
Remove daily limits, process larger files up to 500 MB, enable batch processing, and get priority support.
All Tools Bundle includes:
- All 60+ tools & 21 viewers included
- Unlimited daily uses
- 500 MB file size limit
- All advanced features
- Batch processing
- All export formats
- Priority email support
FAQ
Frequently asked questions about the EML Batch Merge tool
Q1. What is an EML file?
Q2. What is MBOX format?
Q3. Is my email data safe?
Q4. How many EML files can I merge at once?
Q5. Can I reorder the emails before merging?
Q6. What's the difference between MBOX and TXT download?
Q7. Can I open the MBOX file in Thunderbird?
Q8. Does the tool handle attachments in EML files?
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