What is an MHT file?

An mht file extension is associated with the Mime HTML files. MHTML is web archive format used to bind resources and HTML code into a single file. Used mainly on internet and openable with every web browser.

Most Web pages viewed in a Web browser only contain HTML and reference images and other media files that are stored in other directories on the server. Because all the files are encoded into a single file in a MHTML document, MHT files are commonly used to archive Web pages.

NOTE: Microsoft Word can save and open MHTML Web archives.

MHTML, short for MIME Encapsulation of Aggregate HTML Documents, is a web page archive format used to combine in a single document the HTML code and its companion resources that are otherwise represented by external links (such as images, Flash animations, Java applets, and audio files). The content of an MHTML file is encoded as if it were an HTML e-mail message, using the MIME type multipart/related.

In practical terms, MHTML allows multiple elements of a web page—including images and other media that would typically be saved in a folder as separate files alongside an HTML document—to be saved altogether as a single MHTML file. It does so by expanding upon methods originally developed to enrich email content.[1]

The first part of the file is an e-mail header. The second part is normally encoded HTML. Subsequent parts are additional resources identified by their original URLs and encoded in base64. This format is sometimes referred to as MHT, after the suffix .mht given to such files by default when created by Microsoft Word, Internet Explorer, or Opera. MHTML is a proposed open standard, circulated in a revised edition in 1999 as RFC 2557.

The .mhtml (Web archive) and .eml (e-mail file) file extensions are interchangeable (the files can be renamed). The first can be sent by e-mail (and displayed by the email client if the html code is basic enough) and an e-mail message can be saved to an OS file and renamed to a Web archive extension.

How to Open MHT Files

Probably the easiest way to open MHT files is to use a web browser like Internet Explorer, Google Chrome, Opera or Mozilla Firefox (with the Mozilla Archive Format extension).

You can also view an MHT file in Microsoft Word and WPS Writer.

HTML editors can open MHT files too, like WizHtmlEditor and BlockNote.

A text editor can open MHT files as well but since the file might also include non-text items (like images), you won't be able to see those objects in the text editor.

Note: Files ending in the .MHTML file extension are Web Archive files too and are interchangeable with EML files. This means that an email file can be renamed to a Web Archive file and opened in a browser and the Web Archive file can be renamed to an email file to be displayed within an email client.