Glossary
What Is an MHT File?
An MHT file is a web archive, a complete web page saved as one file. Instead of an HTML page with a separate folder of pictures, you get a single document that carries the page text, the images, and the style sheets together. Email it or move it to another disk, and nothing goes missing on the way.
TL;DRAn MHT file is a full web page in a single MHTML file. Open it in Chrome or Edge, and convert it to PDF when it has to open anywhere.
What Is Inside an MHT File
The format is called MHTML, defined in RFC 2557 back in March 1999. It borrows the MIME structure used by email. The file is a multipart/related document, and each piece of the page is a separate part:
- The HTML of the page itself, which is the root part.
- Every image, style sheet, and saved frame, each in its own part.
- A Content-Location header on each part, so links in the HTML find the right resource inside the file.
Because MHTML uses the same MIME layout as a saved email, an MHT opened in Notepad looks a lot like an EML file. Headers sit at the top, a boundary line separates the parts, and each image turns into a long block of Base64 text.
Which Programs Create MHT Files
Three common sources produce almost all the web archives people find on their disks:
- Chrome and Edge: Save page as, then the type Webpage, Single File. These browsers name the file .mhtml.
- Internet Explorer: Save As with the type Web Archive, single file (*.mht).
- Microsoft Word: Save As with the type Single File Web Page, which Word used to call Web Archive.
Chrome and Edge leave scripts out when they save a page, so an archive keeps the look of the page but not its interactive parts.
MHT vs MHTML
.mht and .mhtml are one format. Internet Explorer and Word wrote the shorter .mht extension, while Chrome and Edge write .mhtml. Renaming one to the other changes nothing inside the file.
How to Open an MHT File Today
Drag the file into Chrome or Edge and the saved page appears, images included. Internet Explorer used to be the default program for .mht files, but Microsoft retired the IE11 desktop app on June 15, 2022, and Windows 11 does not ship it at all. If an old archive still points at Internet Explorer, open it with Edge instead.
MHT vs HTML With a Folder vs PDF
A regular saved page is an .html file plus a folder of images and CSS. Move one without the other and the page breaks. MHT fixes that by keeping everything in one file, but it still needs a browser to view and prints the way that browser decides. PDF is the format to choose when the page has to look the same on every device, go to someone who has no browser handy, or sit in an archive for years. Pages saved the old way, as .html with a resource folder, go to PDF with
batch HTML to PDF software.
How to Convert an MHT File to PDF
For one archive, the
free MHT to PDF online tool builds the PDF in your browser. It takes a single .mht or .mhtml file up to 50 MB, and the file is never uploaded. Each PDF page is an image of the web page, so the text cannot be selected or searched.
For a whole folder, the desktop
MHTML to PDF Converter reads every .mht and .mhtml file in a folder and its subfolders. It writes one PDF per archive or combines all pages into one PDF, and it works offline on Windows, rendering pages with Microsoft Edge WebView2.
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