Free online MBOX to XLSX converter

Email applications store messages in MBOX, while Excel and many reporting workflows require XLSX. Converting the archive extracts fields such as sender, recipients, dates, subjects, and message text into editable spreadsheet rows for filtering, analysis, or sharing.

What the MBOX format is

MBOX is a plain-text mailbox format that stores multiple email messages sequentially in one file. Each message contains headers, body content, and sometimes MIME-encoded attachments. Thunderbird, Apple Mail, Eudora, Unix mail systems, and Google Takeout exports can create MBOX files; exported mailboxes and migrated email archives are common places to encounter them.

An MBOX file may have no extension, or it may use .mbox. A single file can contain thousands of messages, but it does not provide the rows-and-columns structure expected by spreadsheet software.

What the XLSX format is

XLSX is the XML-based workbook format used by Microsoft Excel, LibreOffice Calc, and compatible applications. It stores worksheets, typed cells, filters, formulas, formatting, and multiple tables in one compressed file.

XLSX is suitable when email data must be sorted by date or sender, searched with spreadsheet filters, combined with another dataset, or delivered to someone who does not use an email client. It is not an email-archive format: message folders, threading, signatures, inline images, MIME structure, and attachments cannot be represented completely in ordinary cells.

How to actually convert MBOX to XLSX

Use the built-in online converter

1. Open the MBOX-to-XLSX converter on 101convert.com.
2. Upload the MBOX file and select XLSX as the output format.
3. Start the conversion and download the generated workbook when processing finishes.
4. Open the result in Excel or LibreOffice Calc and check the row count, date values, non-ASCII characters, and long message bodies.

This option requires no installed software. Do not upload confidential or regulated mail unless the handling conditions meet your organization’s requirements.

Convert locally with Python

A local script avoids uploading the archive and gives control over the columns. Install the workbook library with python -m pip install openpyxl, save the following as mbox_to_xlsx.py, and run it with python mbox_to_xlsx.py mailbox.mbox mail.xlsx:

import mailbox
import sys
from email.header import decode_header, make_header
from openpyxl import Workbook

def header(value):
    return str(make_header(decode_header(value or '')))

def message_text(message):
    parts = message.walk() if message.is_multipart() else [message]
    output = []
    for part in parts:
        if part.get_content_type() != 'text/plain':
            continue
        if part.get_content_disposition() == 'attachment':
            continue
        data = part.get_payload(decode=True)
        if data is None:
            continue
        output.append(data.decode(part.get_content_charset() or 'utf-8', errors='replace'))
    return '\n'.join(output)

source, target = sys.argv[1], sys.argv[2]
book = Workbook()
sheet = book.active
sheet.title = 'Messages'
sheet.append(['From', 'To', 'Cc', 'Date', 'Subject', 'Message-ID', 'Attachments', 'Body'])

for message in mailbox.mbox(source):
    attachments = []
    for part in message.walk():
        name = part.get_filename()
        if name:
            attachments.append(header(name))
    sheet.append([
        header(message['From']),
        header(message['To']),
        header(message['Cc']),
        header(message['Date']),
        header(message['Subject']),
        header(message['Message-ID']),
        '; '.join(attachments),
        message_text(message)
    ])

book.save(target)

The script writes one message per row and keeps attachment names as a semicolon-separated list; it does not embed attachment files. It extracts text/plain parts, so HTML-only messages may produce an empty body. Add an HTML-to-text conversion step if the archive contains mainly text/html messages.

Quality, compatibility, and limitations

• Excel cell size: Excel limits a cell to 32,767 characters. Longer message bodies must be truncated or split across cells before saving.
• Encoding: Malformed or incorrectly declared character sets can replace accented characters with �. Review multilingual messages after conversion.
• Dates: Keeping dates as text preserves the original header but prevents reliable date sorting. Converting validated headers to timezone-aware datetime values improves filtering.
• Duplicates: MBOX files can contain repeated messages after exports or mailbox repairs. Use the Message-ID column, when present, to identify duplicates.
• Attachments and formatting: XLSX can record attachment names and message text, but it does not preserve the original email’s MIME relationships, inline images, signatures, or folder hierarchy unless separate columns are created.
• Large archives: A workbook becomes difficult to use when it approaches Excel’s worksheet limit of 1,048,576 rows. Split very large mailboxes by folder, date range, or multiple workbooks.