Convert Microsoft Word .docx files to clean, semantic HTML instantly in your browser. Your file is never uploaded — all processing happens locally using mammoth.js.
This tool uses mammoth.js, an open-source JavaScript library developed by Michael Williamson that converts .docx files to clean, semantic HTML. mammoth.js reads the Open XML format inside the .docx file and maps Word's internal styles (Normal, Heading 1, Heading 2, Bold, Italic, Table, List) to their semantic HTML equivalents (<p>, <h1>, <h2>, <strong>, <em>, <table>, <ul>/<ol>).
<h1>–<h6> elements<p> elements<strong> and <em><ol> and <ul><table> elements<a href="..."> elementsPasting from Word into an HTML editor or CMS brings along all of Word's proprietary markup: class="MsoNormal", inline style attributes with font names and sizes in points, non-breaking spaces, empty paragraphs, and nested spans. This markup is not only visually broken (it overrides your site's CSS) but bloats your HTML by 3–10× compared to clean semantic markup. mammoth.js extracts only the semantic meaning, discarding all the proprietary formatting. If any leftover classes or attributes remain in the output, pass the result through our html cleaner online to strip them out in one click, or convert the finished HTML to HTML to PDF for distribution.
No. Your .docx file is read directly in your browser using the FileReader API and processed entirely by mammoth.js running in JavaScript. The file never leaves your device and is never sent to any server. This tool is safe for confidential business documents.
No. mammoth.js only supports the modern .docx format (Office Open XML), which has been the default in Microsoft Word since Office 2007. If you have an older .doc file, open it in Word, Google Docs, or LibreOffice and save or export it as .docx before converting.
mammoth.js focuses on semantic HTML conversion. Footnotes, endnotes, tracked changes, comments, and WordArt are not supported and will be ignored or produce a conversion warning. For production use cases with complex documents, the conversion warnings (displayed as a toast notification) identify elements that could not be converted.
For server-side conversion, use the mammoth.php library (a PHP port of mammoth.js) via Composer: composer require phpoffice/phpword. Alternatively, PHPWord and PhpSpreadsheet both support reading .docx and exporting to various formats, though semantic HTML output quality varies. For the cleanest results, use this browser-based tool and host the resulting HTML.