Markdown to HTML Converter

What Is Markdown?

Markdown is a lightweight plain-text format for writing structured content, created by John Gruber in 2004 with a simple goal: a document should be readable as plain text and still convert cleanly to HTML. Instead of writing <h1>Title</h1> you write # Title; instead of <strong>word</strong> you write **word**. The format caught on because it removes the markup noise from writing — you never fight angle brackets while composing — while still producing well-formed HTML at the end. Today Markdown is the default writing format for GitHub READMEs, package documentation, note-taking apps, forum posts, chat clients, and most static-site generators, which is why a reliable Markdown-to-HTML converter is a genuinely everyday tool.

Why Convert Markdown to HTML?

The conversion is needed every time Markdown content has to live somewhere that expects HTML: pasting a README's worth of notes into a CMS rich-text field, building an HTML email from a Markdown draft, embedding formatted content into a webpage that does not run a Markdown processor, publishing a blog post whose pipeline takes HTML directly, or preparing content for a documentation site that accepts pasted HTML. Rather than hand-translating every heading and list, you paste the source and take the finished markup — consistent, well-nested, and escaped. For people who write in Markdown and publish in HTML, the converter is the bridge between the two.

Supported Syntax at a Glance

# Heading

<h1>Heading</h1>

**bold** and *italic*

<strong>bold</strong> and <em>italic</em>

`code` and ~~strike~~

<code>code</code> and <del>strike</del>

- one
- two

<ul>
<li>one</li>
<li>two</li>
</ul>

1. first
2. second

<ol>
<li>first</li>
<li>second</li>
</ol>

[text](https://example.com)

<a href="https://example.com">text</a>

<https://example.com>

<a href="https://example.com">https://example.com</a>

How the Converter Works

The conversion happens in two passes. The block pass walks the input line by line and recognizes the document's structure — headings, fenced code blocks, tables, blockquotes, lists, horizontal rules, and paragraphs — emitting the matching tags with correct nesting. The inline pass then processes the text inside each block, recognizing emphasis (**bold**, *italic*, ~~strikethrough~~), inline code, links, images, and autolinks. Throughout, every piece of plain text is HTML-escaped before emission, which is what makes the output safe: angle brackets, ampersands, and quotes in your source become their escaped entities, so pasted HTML or a stray <script> renders as visible text instead of executing. The two passes also mirror the two layers of the Markdown spec itself — block structure and inline content — which keeps the output predictable.

Standards: CommonMark and GitHub Flavored Markdown

Markdown's original spec was famously loose, so in 2014 the community standardized the core as CommonMark — a precise grammar with conformance tests, adopted by GitHub, Reddit, and most tooling. On top of it, GitHub added a handful of extensions that make up GitHub Flavored Markdown (GFM): tables, strikethrough, autolinks, and task lists. This converter implements the CommonMark-style core — ATX headings, fenced code blocks, blockquotes, lists, emphasis, inline code, links, images — plus GFM tables and strikethrough, which covers the syntax used in the overwhelming majority of real documents. It deliberately skips the corner cases that confuse more than they help; the troubleshooting section below lists exactly what is not supported.

Worked Example: A Short Document

Paste this short document into the tool — the output should match exactly:

# Release Notes

**Today** we shipped `v2.0` with:

- Faster startup
- A new [docs site](https://example.com)

> Feedback welcome!

The expected HTML output:

<h1>Release Notes</h1>
<p><strong>Today</strong> we shipped <code>v2.0</code> with:</p>
<ul>
<li>Faster startup</li>
<li>A new <a href="https://example.com">docs site</a></li>
</ul>
<blockquote>
<p>Feedback welcome!</p>
</blockquote>

Notice the shape of the output: each block becomes one element at the correct nesting depth, the list is a single <ul> containing <li> items, the blockquote wraps its own paragraph, and the inline emphasis and link live inside the paragraph text. There are no stray tags and no unescaped characters — exactly what you want to paste into a page.

What This Converter Deliberately Doesn't Do

A few things are intentionally out of scope, and knowing them avoids surprises. Nested lists (a list inside a list item) are not supported — flatten them or restructure. Setext headings (a line of === or --- under a paragraph) are not implemented; use # headings. Underscore emphasis is ignored so identifiers like my_var and snake_case pass through untouched — use asterisks for emphasis. Raw HTML passthrough is disabled for safety: HTML in the source is escaped and shown as text. And link titles ([text](url "title")) are not parsed — the URL itself is used. Each of these choices trades a rare syntax for predictability and safety, which suits a converter that handles pasted, possibly untrusted, content.

Troubleshooting & Common Mistakes

Indented Code vs. Fenced Code

This converter recognizes fenced code blocks (```) but not four-space-indented code. If your code block is indented, wrap it in backtick fences instead — or accept that it will render as a paragraph.

Lists Running Together

A list ends at a blank line or a line that is not a list item. If two lists run together without a blank line between them, they merge into one — add a blank line to separate them.

Unclosed Code Fences

A fence that is never closed swallows the rest of the document into the code block. Always close what you open — the converter treats the end of input as the closing fence, so an unclosed fence is a silent bug rather than an error.

Underscore Italics Not Working

_text_ is not treated as emphasis. Use *text* for italics — the underscore rule exists to protect identifiers and is unlikely to change.

Frequently Asked Questions