Convert PDF to MHT

A legacy document-management system or browser archive may accept only MHT, while the source document is available as a PDF. Converting it creates a single web archive for that workflow, but it can change the PDF’s layout, text structure, and interactive features.

What the PDF format is

PDF, or Portable Document Format, is a page-description format standardized as ISO 32000. It can contain text, embedded fonts, images, vector graphics, metadata, annotations, forms, attachments, encryption, and digital signatures. Adobe Acrobat, Microsoft Word, LibreOffice, web browsers, scanners, print drivers, and publishing software create PDFs for reports, invoices, manuals, legal records, scanned pages, and documents that must print consistently across operating systems.

What the MHT format is

MHT, also called MHTML, is a MIME multipart/related web archive. It packages an HTML document and referenced resources such as images, stylesheets, and sometimes scripts into one file, usually with the .mht or .mhtml extension. Binary resources are commonly encoded inside the MIME message rather than stored as separate files.

An MHT file is useful when an older Windows application, Internet Explorer-based workflow, or document archive requires one self-contained web page. It is easier to move than an HTML file accompanied by an assets folder, but it is not a page-layout format and is less consistently supported by modern browsers than PDF.

How to convert a PDF to MHT

The most practical desktop method is Microsoft Word for Windows. Word imports the PDF into an editable document and then exports that reconstructed content as an MHT file; it does not preserve the original PDF page model inside the archive.

1. Open Word and select File → Open → Browse.
2. Select the source file, such as document.pdf, and accept Word’s PDF-conversion warning.
3. Inspect the imported pages for shifted text, missing fonts, broken tables, misplaced images, and changed page breaks.
4. For a scanned PDF, run OCR in Adobe Acrobat or another OCR application before importing it. An image-only PDF does not provide Word with normal editable text.
5. Select File → Save As → Browse, set Save as type to Single File Web Page (*.mht; *.mhtml), choose a filename such as document.mht, and select Save.
6. Open the result in the exact application that will use it. Check images, hyperlinks, special characters, page order, and any required scripts or embedded resources.

Word’s available web-page formats can vary by edition and platform. If Single File Web Page is absent, that Word installation cannot directly produce MHT; exporting ordinary HTML creates an HTML file and a separate resource folder, not an MHT archive.

Using an online converter

Reputable services such as Zamzar or Convertio may list MHT or MHTML as an output format, but format availability can change. Confirm that .mht or .mhtml appears in the service’s current output list before uploading the PDF, then upload the file, select the output format, start the conversion, download the result, and remove uploaded data when the service provides that option.

Do not upload confidential, regulated, proprietary, or digitally signed PDFs unless the provider’s processing, retention, deletion, and location policies satisfy the applicable requirements. A local Word conversion avoids transferring the source document to a third party.

Quality and compatibility limits

• Layout: Conversion usually reconstructs each page as HTML. Fixed-position elements, columns, tables, footnotes, transparency, line wrapping, and font metrics can change.
• Scans: Without OCR, a scanned PDF may become an MHT containing page images with no selectable or searchable text.
• PDF features: Signatures, comments, attachments, bookmarks, form controls, encryption, multimedia, layers, and accessibility metadata may be removed or altered. Validate a signature against the original PDF, because changing formats invalidates the original signed content.
• Security: MHT files can contain active content in some legacy environments. Treat files from untrusted sources as potentially unsafe and test them in the target application’s restricted or controlled environment.
• Browser support: Native MHT handling is inconsistent in current Edge, Chrome, and Firefox releases. Test the file in the specific legacy program that requires it rather than relying on a modern browser preview.
• Preservation: Keep the original PDF alongside the MHT. PDF is generally the better archival copy when exact appearance, signatures, annotations, or long-term accessibility matter.