Markdown to HTML Converter
Convert Markdown to HTML and HTML to Markdown in real time. Live preview, GitHub-flavored syntax, code highlighting, table of contents, sanitization, themes, file upload, URL fetch & full export — all client-side.
How to Use the Markdown to HTML Converter
- Pick a mode: Markdown → HTML, HTML → Markdown, or Live Preview (side-by-side editor).
- Type or paste your content, upload a file (.md, .markdown, .html), fetch from a URL, or load a sample.
- Toggle options — pick a theme (GitHub, Clean, Bootstrap, Dark, Minimal), enable GFM tables, syntax highlighting, HTML sanitization, auto-TOC, emoji shortcodes.
- Switch between Rendered view and raw Code view of the output.
- Copy as plain text or rich (paste straight into Word/Docs), download as
.htmlor.md, print to PDF, or share via URL. - Use Swap I/O to round-trip — turn output into input and back to verify accuracy.
What is Markdown?
Markdown is a lightweight markup language created by John Gruber in 2004 that lets you write formatted text using plain-text syntax. It's the de-facto standard for README files on GitHub/GitLab, documentation sites, static blogs (Jekyll, Hugo, 11ty), Notion-style note-taking apps, Reddit/Discord/Stack Overflow comments, and AI chat outputs.
This converter uses marked.js — the most widely-deployed JavaScript Markdown parser — with full GitHub Flavored Markdown (GFM) support: tables, task lists, autolinks, strikethrough, fenced code blocks, and more. For the reverse direction (HTML → Markdown) it uses turndown, the industry standard. Code highlighting is powered by highlight.js (170+ languages), and HTML output is optionally sanitized through DOMPurify to strip dangerous tags.
Everything runs 100% in your browser — no upload, no signup, no logs.
Common Use Cases
Why Choose Our Markdown Converter?
Frequently Asked Questions
Which Markdown flavor does this support?
CommonMark plus GitHub Flavored Markdown (GFM) — tables, task lists (- [x]), strikethrough (~~text~~), autolinks, fenced code blocks with language hints, footnotes, definition lists. It's the same dialect used by GitHub, GitLab, Bitbucket and most modern static-site generators.
What's the difference between "Copy" and "Copy rich"?
Copy copies the raw HTML source code (good for pasting into a CMS or HTML file). Copy rich copies the rendered output as formatted text — paste into Word, Google Docs, Outlook, Notion or any rich-text editor and formatting is preserved.
Is the HTML output safe to embed on my site?
If the Sanitize HTML option is on (default), output is run through DOMPurify which strips <script> tags, event handlers (onclick etc.), and javascript: URLs. Even with sanitization off, our tool itself doesn't add anything malicious — but be cautious converting Markdown from untrusted sources with sanitization disabled.
How accurate is the HTML → Markdown conversion?
Excellent for most common HTML — headings, lists, links, tables, code blocks, bold/italic, blockquotes. Less perfect on heavily nested or visually-styled HTML (complex CSS layouts, custom components). The conversion is best-effort and produces clean readable Markdown.
Does it support math (LaTeX)?
Inline LaTeX ($x^2$) and block LaTeX ($$\sum_{i=1}^n$$) render as plain text — to enable rendered math, copy the HTML output and add MathJax or KaTeX to your destination page.
Does it support Mermaid diagrams?
Mermaid code blocks are kept intact in the HTML output. Add the Mermaid script to your destination page to render them.
What about embedded HTML inside my Markdown?
marked.js passes raw HTML through. If Sanitize is on, dangerous tags get stripped. Otherwise your HTML is preserved as-is.
What's the file size limit?
Soft limit of about 5 MB. Beyond that, browsers begin to struggle with live rendering.
Is my content uploaded anywhere?
No. Everything is processed locally in your browser. The only network call is the optional URL-fetch feature.