Markdown to HTML Converter

Markdown to HTML conversion explained

Markdown is a plain-text formatting syntax that compiles to HTML, created in 2004 by John Gruber with Aaron Swartz. Its stated design goal was that a Markdown document should be publishable as-is - readable without looking like it has been marked up at all. That constraint is why the syntax borrows conventions people already used in email: asterisks for emphasis, hyphens for bullets, indentation for code.

It became the default authoring format for a large slice of the web: README files on GitHub and GitLab, documentation built with Docusaurus or MkDocs, static sites from Hugo, Jekyll, and Astro, and note tools including Obsidian and Notion. One consequence of Gruber's original specification being informal English prose rather than a grammar is that implementations diverged badly, which is what prompted CommonMark in 2014 - a strict specification with a test suite - and GitHub Flavored Markdown, which layers tables, task lists, strikethrough, and autolinking on top of CommonMark.

When you write # My Heading in Markdown, this tool converts it to <h1>My Heading</h1>. Write **bold**, get <strong>bold</strong>. The mapping is straightforward and predictable.

Common use cases for this Markdown to HTML converter:

• CMS publishing: Write in Markdown, paste HTML into a WordPress or Webflow rich text field
• Email templates: Convert Markdown to HTML for transactional emails or newsletters
• Documentation: Convert README.md files to embeddable HTML snippets
• Blog migration: Convert legacy HTML content to clean Markdown for a new static site
• Learning: See exactly how Markdown syntax maps to HTML tags

The reverse direction - HTML to Markdown - is equally useful. When you copy content from a webpage or CMS and want a clean plain-text representation, HTML to Markdown strips the tags and returns readable, portable Markdown syntax.

Why the two directions are not symmetrical

Markdown to HTML is a clean compilation: every construct has exactly one output, so the result is predictable. Going backwards is lossy by nature, because HTML can express far more than Markdown can. A <div> with classes, a <table> with merged cells via colspan, an inline style attribute, or a <figure> with a caption have no Markdown equivalent at all. Converters typically either drop the wrapper and keep the text, or pass the raw tag through - since Markdown permits inline HTML by design. Expect to tidy the output of any HTML-to-Markdown pass by hand.

Common friction points when converting either way:

• Single line breaks are not <br>. Markdown joins consecutive lines into one paragraph; you need two trailing spaces, a backslash, or a blank line for a real break
• Underscores inside words - snake_case_name can trigger emphasis in older parsers; CommonMark fixed this, but escaping with a backslash is safest
• Nested lists need consistent indentation, usually two or four spaces, and mixing tabs with spaces produces unpredictable nesting
• Fenced code blocks beat indented ones - triple backticks allow a language hint for syntax highlighting, which four-space indentation cannot carry
• Bare URLs autolink under GFM but not under strict CommonMark; wrap them in angle brackets to be certain

One security note if you are pasting the HTML output into a live site: Markdown allows raw HTML, so untrusted Markdown can contain a <script> tag or a javascript: link. Never render user-submitted Markdown without running the resulting HTML through a sanitiser such as DOMPurify.

Conversion in both directions runs as JavaScript inside this page. Nothing is uploaded, there is no character limit, and the tool keeps working offline once the page has loaded - so internal documentation and unpublished drafts are safe to paste.