Browse Tools Top 100
MHT MHTML
File conversion

Convert MHT to MHTML

Verified by Adam B.· reviewed by FE Editorial ·updated Jun 14, 2026
QUICK ANSWER
Is it possible to convert MHT to MHTML?
Yes - MHT converts to MHTML.

The MHTML format (RFC 2557) has two accepted file extensions: .mht (popularized by Internet Explorer 5) and .mhtml. No conversion is needed - rename the file and it works identically. The only reason to rename is that some applications, CMS platforms, or web servers look for one extension specifically.

Also to MHTML: MAFF

On this page

Tested on macOS, Windows & Linux
Last verified Nov 2026

More free converters

HEIC, PNG, WEBP, MP3 and more - every tool here is free.

Open the toolbox

Why convert MHT to MHTML?

.mht and .mhtml are two names for one format (MIME HTML, RFC 2557); the file content, MIME headers, HTML, embedded images, and CSS are byte-for-byte identical under either extension. Microsoft coined .mht for Internet Explorer 5 in 1999; .mhtml is the more standard name matching the format's official acronym.

How to convert MHT to MHTML

Windows File Explorer FREE

Right-click the .mht file, choose Rename (or press F2), and change the extension to .mhtml. Confirm the extension change when Windows prompts.

PowerShell FREE

Run Rename-Item file.mht file.mhtml in PowerShell. For multiple files, use Get-ChildItem *.mht | Rename-Item -NewName { $_.Name -replace '.mht$', '.mhtml' }.

Terminal FREE

Run mv file.mht file.mhtml in Terminal on macOS or Linux. The file content is untouched; only the extension changes.

About these formats

.MHT MIME HTML Web Archive (MHTML)

An MHT (MHTML) file is a complete web page - the HTML, images, CSS, and scripts - bundled into one file using the same MIME packaging email uses. Open it by dragging it into Microsoft Edge…

Open .MHT details →
.MHTML MIME HTML (MHTML) Web Page Archive

An MHTML (.mhtml or .mht) file is a complete web page - HTML, images, CSS, and scripts - bundled into one file for offline viewing. Open it by dragging it into Microsoft Edge or Google…

Open .MHTML details →

Quality & what to watch

  • No data is lost or changed; the MIME headers, HTML, embedded images, CSS, and Base64-encoded resources remain completely untouched when you rename.
  • Microsoft Edge and Google Chrome open both .mht and .mhtml natively; Firefox requires an extension for either.
  • Some web servers send the wrong Content-Type header for .mht files; renaming to .mhtml can fix browser behavior when accessing the file over HTTP.

Frequently asked questions

Is there any difference between a `.mht` and a `.mhtml` file?
No - both extensions refer to the same MHTML format (RFC 2557); the content and internal structure are identical.
Will renaming affect how browsers open the file?
Edge and Chrome open both extensions equally well; the rename only matters for systems that check the file extension.
Why does the `.mht` extension exist at all?
Microsoft coined .mht for Internet Explorer 5 in 1999; .mhtml is the more standard name and matches the format's official acronym.
Can I batch rename many `.mht` files at once?
Yes - in PowerShell, Get-ChildItem *.mht | Rename-Item -NewName { $_.Name -replace '.mht$', '.mhtml' } renames all .mht files in the current folder.