Free Online Markdown to HTML Converter
A browser-based editor that converts Markdown to clean HTML — and HTML back to Markdown — entirely on your device. No files leave your browser. No account needed. Supports GitHub Flavored Markdown, LaTeX math equations, Mermaid diagrams, and custom HTML rules.
Live Preview
Output updates as you type with a 300ms debounce. Split-pane view keeps source and rendered HTML visible side by side.
Two-way Conversion
Swap modes in one click. Convert Markdown to HTML or paste HTML and retrieve clean, structured Markdown — tables included.
LaTeX Math
Render equations with KaTeX. Supports $...$, $$...$$, \(...\), and \[...\] delimiters.
Mermaid Diagrams
Write flowcharts, sequence diagrams, and Gantt charts directly in Markdown using fenced ```mermaid blocks.
Export Options
Download a raw HTML fragment, a complete standalone HTML file with embedded styles, or send the page to your printer.
Privacy First
Everything runs in your browser. Content is auto-saved to localStorage only — nothing is uploaded to any server.
How to Use This Converter
You can be writing and previewing Markdown in seconds.
Write or paste your Markdown
Type directly into the left editor panel, paste existing Markdown, or drag and drop a
.md, .markdown, or .txt file anywhere onto the editor.
The toolbar above the editor lets you insert headings, bold, links, tables, and code blocks without typing syntax.
See the live HTML preview
The right panel renders your Markdown as HTML in real time. Switch to the Raw HTML tab to inspect the generated markup. Math equations are rendered by KaTeX, diagrams by Mermaid.js. Enable Sync Scroll to lock both panels to the same reading position.
Copy or download the output
Click the copy icon to grab the HTML to your clipboard. Use the download button for a raw
.html fragment, or the standalone export button for a complete HTML file
with KaTeX styles and all your custom CSS baked in — ready to host anywhere.
Convert HTML back to Markdown (optional)
Click the swap button in the toolbar to switch to HTML-to-Markdown mode. Paste any HTML and the tool produces clean, readable Markdown — preserving GFM tables, code fences, and heading levels. Useful for migrating content between platforms.
Markdown Syntax Cheat Sheet
The most frequently used Markdown elements and their HTML equivalents.
| Element | Markdown syntax | HTML output |
|---|---|---|
| Heading 1 | # Heading |
<h1>Heading</h1> |
| Heading 2 | ## Heading |
<h2>Heading</h2> |
| Bold | **bold text** |
<strong>bold text</strong> |
| Italic | *italic* |
<em>italic</em> |
| Strikethrough | ~~deleted~~ |
<del>deleted</del> |
| Link | [text](https://...) |
<a href="...">text</a> |
| Image |  |
<img alt="alt" src="..."> |
| Inline code | `code` |
<code>code</code> |
| Code block | ```lang |
<pre><code>...</code></pre> |
| Blockquote | > quoted text |
<blockquote>...</blockquote> |
| Unordered list | - item |
<ul><li>item</li></ul> |
| Ordered list | 1. item |
<ol><li>item</li></ol> |
| Horizontal rule | --- |
<hr> |
| Table (GFM) | | A | B | |
<table>...</table> |
| Inline math | $E = mc^2$ |
KaTeX rendered equation |
| Block math | $$...$$ or \[...\] |
KaTeX display equation |
Frequently Asked Questions
$...$ or \(...\). For display (block) equations, use
$$...$$ on its own line or \[...\]. All four syntaxes are rendered by KaTeX,
so the full range of LaTeX math commands is available. Currency like $5 is not treated
as math because the parser requires a non-space, non-digit character after the opening dollar sign.
mermaid is automatically
rendered as a diagram. Mermaid.js supports flowcharts (graph LR), sequence diagrams,
Gantt charts, class diagrams, entity-relationship diagrams, and more. The library is lazy-loaded
only when a diagram is detected, so it does not slow down regular Markdown conversion.
.html file with a full <head>, embedded KaTeX
styles, Mermaid SVG graphics, and any custom CSS you wrote in the editor — ready to open in a
browser or host as a static page.
localStorage
after every edit — one slot for Markdown content and one for HTML content. When you return
to the page, your last session is restored automatically. Nothing is stored on any server.
You can clear the editor at any time using the trash icon in the toolbar.
<style> block directly in your Markdown. In the live
preview, selectors are automatically scoped to the preview panel so they cannot affect the rest
of the page. When you download a standalone HTML file, the styles are included unscoped and apply
globally within that document — exactly as you wrote them.