MBOX Counter
Count the emails in an MBOX file instantly — plus attachments, date range, top senders and messages per year.
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Runs entirely in your browser — nothing is uploaded
How to use the MBOX Counter
- 1
Open your MBOX file
Click the box or drag the file onto it. It’s read by your browser — nothing is uploaded.
- 2
Read it instantly
The content appears on the page in a second or two, even for large files.
- 3
Convert if you need to
Use the related converters below to turn the file into PDF, CSV or another format.
Check a mailbox export before migrating it, or verify a backup is complete. The counter scans only message headers, so even multi-gigabyte MBOX files are counted in seconds, without uploading anything.
Read the full guide with screenshotsFrequently asked questions
Is the MBOX Counter free?
Yes — completely free with no daily limit and no account. ZapMorph’s viewers and developer tools are unmetered.
Is my file uploaded to a server?
No. The file is opened by your browser and displayed on this page. It is never uploaded, stored or logged — close the tab and it’s gone.
Does it work on my phone?
Yes. It works in any modern browser on iPhone, Android, Windows, Mac and Linux, with nothing to install.
How large can the file be?
There is no fixed limit — it depends on your device’s memory. Files of a few hundred megabytes open fine on most computers.
Related converters
MBOX to CSV
MBOXCSV
Export MBOX mailboxes to a CSV spreadsheet — one row per email with date, sender, subject and body.
MBOX to PDF
MBOXPDF
Convert MBOX mailboxes to PDF with sender, recipients, date and message body. Private — nothing is uploaded.
MBOX to EML
MBOXEML
Convert MBOX mailboxes to standard EML files that open in Thunderbird, Apple Mail and Outlook.
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Open and read PDF files online with zoom and page navigation. Nothing is uploaded — the PDF opens on your device.
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EML Viewer
Open .eml email files online and read the message, headers and attachments. Nothing is uploaded.
MSG Viewer
Open Outlook .msg files on Mac, Windows, Linux or phone — read the email and save attachments.
PST Viewer
Open Outlook PST files without Outlook: browse folders, search and read emails, and save attachments. Private.
Excel Viewer
Open XLSX spreadsheets online and browse every sheet as a table — no Excel required. Private, in-browser.