How to Convert MBOX to HTML: Step-by-Step Guide

Published By Anurag Sharma

Published On October 13th, 2026

Reading Time 8 Minutes Reading

Category Technology

If you want to convert MBOX to HTML, import the MBOX format file into Mozilla Thunderbird, install the ImportExportTools NG add-on, and export the file in HTML format. For large files or folder, use a dedicated offline converter tool, which helps you export all emails in one go without requiring any prior knowledge of coding or any technical skill.

Let’s dive deep into the methods and solutions for how to convert MBOX to HTML, covering both manual and offline software solution, which enables you to export all emails without code involved.

Why Do We Need to Convert MBOX to HTML?

Conversion of MBOX to HTML is most useful for individuals changing email clients, or want to read old mails or share emails with legal or IT teams that need to share it with others.

When you convert emails to HTML, it unlocks a step to convenience and efficiency in sharing and organizing emails without email clients.

How to Convert MBOX to HTML? Methods Explained

There are two ways to convert MBOX to an HTML formatting- a manual method and using a dedicated converter.

Method 1: Convert MBOX to HTML Manually (Free)

There are two options available for doing this conversion manually– use Thunderbird which does not require coding skills or else, you can use a Python script.

Option A: Use Thunderbird (No Coding)

Mozilla Thunderbird is a free email client and with a help of an add-on like ImportExportTools NG, you can export its emails as HTML.

Follow these steps–

• Step 1: Install Thunderbird and open its dashboard.
• Step 2: Go to Add-ons, search for ‘ImportExportTools NG’, and install it.
• Step 3: Click on ‘Local Folders’, then select ‘ImportExportTools NG’, then ‘Import mbox file’.
• Step 4: Import file(s) or folder you want to convert and export.
• Step 5: after choosing the files, open the import folder and select option ‘Export all messages in the folder’, and at last choose ‘HTML’ as the export format.
• Step 6: Select a destination folder on your local device, and now you can open any file in the browser just by double-clicking on it.

Option B: Use a Python Script (All-in-One File)

The python script to convert MBOX to HTML helps to combine all your emails into a single HTML page with a clickable index. Each email is placed inside a sandboxed frame, so pages do not get affected by any styling or scripts.

import mailbox
import html
from email.header import decode_header, make_header
def decode(value):
return str(make_header(decode_header(value))) if value else ""
def get_body(msg):
if msg.is_multipart():
for part in msg.walk():
disposition = str(part.get("Content-Disposition"))
if part.get_content_type() == "text/plain" and "attachment" not in disposition:
payload = part.get_payload(decode=True)
if payload:
return payload.decode(part.get_content_charset() or "utf-8", errors="replace")
else:
payload = msg.get_payload(decode=True)
if payload:
return payload.decode(msg.get_content_charset() or "utf-8", errors="replace")
return ""
mbox = mailbox.mbox("input.mbox")
with open("output.html", "w", newline="", encoding="utf-8-sig") as f:
writer = html.writer(f)
writer.writerow(["From", "To", "Cc", "Subject", "Date", "Body"])
for msg in mbox:
writer.writerow([
decode(msg["From"]),
decode(msg["To"]),
decode(msg["Cc"]),
decode(msg["Subject"]),
msg["Date"],
get_body(msg).replace("\n", " ").strip(),
])

Follow these steps–

• Step 1: Download and install the MBOX to HTML converter on your Windows or Mac from Revove’s original website.

• Step 2: Click Add File (or Files) option to add one or multiple MBOX files to convert.

• Step 3: Preview your selected files to confirm you loaded the correct files.

• Step 4: Select the destination folder, where you want to save the HTML files.

• Step 5: Select the export format as HTML, by choosing it from the given list of formats.

• Step 6: Choose the fields you need to export from the given options and apply filters.

• Step 7: Click Convert, and then you can open the file in Excel or Google Sheets.

Features That Matter in an MBOX to HTML Converter

• Multiple files can be processed at once.
• Preserves formatting and images in emails.
• Offers filters like date, sender, and subject to show only specific part in the HTML file after conversion.
• Works completely offline with no third-party server involved.
• Does not require installation of any email client like Thunderbird.

Which MBOX to HTML Method Should You Choose?

Conclusion

If you are looking for easy and reliable methods that can convert MBOX to HTML, first check what type of file you need to convert. Thunderbird or a Python script works for small, one-time conversion requirements. You can split large MBOX files into smaller files, or the convert large, bulk, or confidential emails using an offline MBOX to HTML converter. It is the optimal choice in this case. But keep in mind, before applying any method on your file, always back up your files before testing or test a method using a sample file.

FAQs about MBOX to HTML

1. How much time does it take to convert MBOX to HTML?
   Ans. The time duration highly depends upon the file size and method. A small MBOX file can be converted in minutes while a large or bulk files can take unusual time to process in Thunderbird. A converter tool can easily process both types of files faster than Thunderbird or a Python code.
2. Can I convert MBOX to HTML without internet connection?
   Ans. Yes. Thunderbird, Python scripts, and even dedicated tools work offline and convert your MBOX files to HTML.
3. Is there a limit for file size for conversion to HTML?
   Ans. Most manual methods do not have any file size limit, but can work comparatively slow on large MBOX files. An offline converter handles large files more reliably and converts faster.
4. Can converted HTML email files open in every browser?
   Ans. Yes. HTML is a standard format, and can be opened in Chrome, Edge, Firefox, Safari, and mobile browsers as well.
5. Can I convert MBOX to HTML on Mac?
   Ans. Yes. The Revove offline converter has versions available, both for Windows and Mac. You should carefully check the prerequisites of the tool before using it.