A free web tool that turns Markdown (.md) into HTML and converts HTML back into Markdown. Nothing to install, no sign-up, and no file ever leaves your machine — every conversion runs inside your browser.
Markdown is pleasant to write but it does not look like a finished document on its own.
GitHub and Notion render it for you; the moment a .md file leaves those walls,
the reader sees raw #, ** and | characters.
That is where converting to HTML helps.
It does more than move paragraphs across. GFM tables and task lists, syntax highlighting for fenced code, Mermaid diagrams and LaTeX math (KaTeX) all come through. Mermaid diagrams are rendered to images before export, so whoever opens the file sees the diagram without installing anything.
Images work the same way. Drop in the picture files your document references and they are matched by filename and embedded directly into the HTML. What you get back is a single file with the images inside — attach it to an email or copy it to a USB stick and nothing breaks.
Converting HTML back to Markdown happens on the same screen. Drop an .html file,
paste content copied straight from a web page, or enter a URL and the page is fetched for you.
Tables and code-block languages are kept when converting back as well, which makes it a
practical way to pull something you read on the web into your own Markdown notes.
Conversion happens entirely in the browser and document contents are never transmitted. Internal documents and unpublished drafts are safe to use here. You can also drop several files at once, review them one by one, then download them individually or all together as a ZIP. The interface is available in English and Korean.