Markdown to HTML

Convert Markdown text to clean HTML with GitHub-flavored markdown support.

What is Markdown to HTML Conversion?

Markdown is a lightweight markup language created by John Gruber in 2004. It uses plain-text syntax — like # for headings, ** for bold, and [text](url) for links — to produce formatted text that is both human-readable and convertible to HTML. HTML (HyperText Markup Language) is the standard markup language for documents designed to be displayed in a web browser. Converting Markdown to HTML transforms those simple text shortcuts into proper HTML tags like <h1>, <strong>, and <a href="..."> that browsers can render directly.

The conversion process is powered by the marked library, a fast and feature-rich Markdown parser for JavaScript. It supports the CommonMark specification as well as GitHub Flavored Markdown (GFM), which adds tables, strikethrough, task lists, and automatic link detection. The parser processes your Markdown in real-time entirely in your browser — no data is sent to any server, ensuring complete privacy and security.

Our converter also includes a built-in sanitization layer that strips potentially dangerous HTML elements such as <script>, <iframe>, and <object> tags, as well as event handler attributes like onclick and onerror. This protects against Cross-Site Scripting (XSS) attacks when rendering untrusted user-generated Markdown content on your website. Additionally, the tool neutralizes javascript: protocol links that could execute arbitrary code.

An optional Heading IDsfeature generates URL-safe slug attributes for every heading (h1–h6) in your document. For example, a heading like "Getting Started" becomes <h2 id="getting-started">, enabling deep-linking and table-of-contents navigation. This is particularly useful for documentation sites, blog posts, and knowledge bases where readers need to jump directly to specific sections via anchor links.

Markdown to HTML conversion is used everywhere in modern web development: README files on GitHub and npm are rendered from Markdown, static site generators like Next.js, Astro, and Hugo transform Markdown into HTML pages, CMS platforms accept Markdown from contributors and store it as HTML, documentation systems like Docusaurus and MkDocs are built on Markdown, and many chat platforms including Slack and Discord support a subset of Markdown for message formatting.

How to Use Markdown to HTML Converter

Type or paste your Markdown content into the left editor pane. You can also click Load Example to try the tool with sample content.
Toggle GFM to enable GitHub Flavored Markdown features like tables, strikethrough, and task lists. This is on by default.
Toggle Breaks to convert single line breaks (\n) into <br> tags. By default, single line breaks are ignored (standard CommonMark behavior).
Toggle Heading IDs to add id attributes to all headings for anchor linking.
The HTML output appears automatically in the right pane as you type, with a 300ms debounce for smooth performance.
Use the Copy HTML button to copy the generated HTML to your clipboard.
Use the Download button to save the output as an .html file.
Click Clear to reset both input and output fields.

Supported Markdown Features

Headings — All six levels (# through ######) with optional id attributes for anchor links.
Text formatting — Bold (**text**), italic (*text*), strikethrough (~~text~~, GFM), and inline code (`code`).
Lists — Ordered lists, unordered lists, nested lists, and GFM task lists with checkboxes (- [x] / - [ ]).
Links and images — Standard links, auto-linked bare URLs (GFM), and image embeds with alt text.
Code blocks — Fenced code blocks with optional language classes for syntax highlighting (```js), and inline code.
Tables (GFM) — Full table support with headers, alignment, and multiple columns.
Blockquotes — Nested blockquotes for quoting text.
Horizontal rules — ---, ***, or ___ for thematic breaks.
HTML passthrough — Raw HTML in Markdown is preserved (with sanitization enabled by default for safety).

GFM vs CommonMark

CommonMark is a formal specification for Markdown that aims to resolve ambiguities in the original Markdown syntax. It defines a strict, predictable parsing algorithm so that different Markdown processors produce identical output for the same input. CommonMark covers the core features: headings, paragraphs, bold and italic text, lists, links, images, code blocks, blockquotes, and horizontal rules. It is the foundation that most modern Markdown parsers build upon.

GitHub Flavored Markdown (GFM) is a strict superset of CommonMark, developed by GitHub. It adds several extensions that are not part of the CommonMark spec:

Tables — Pipe-delimited tables with header rows and alignment markers.
Strikethrough — ~~text~~ renders as ~~text~~.
Task lists — Checkbox-style list items for to-do tracking.
Autolinks — Bare URLs like https://example.com are automatically converted to clickable links.
Disallowed raw HTML — GFM provides rules for filtering certain HTML elements.

When GFM is enabled (the default), our converter produces output compatible with what you would see on GitHub, npm, or any platform that renders GFM. Disabling GFM switches to pure CommonMark mode, which omits tables, strikethrough, task lists, and autolinking. This can be useful when you need output that adheres strictly to the CommonMark specification, or when targeting platforms that only support basic Markdown.

The Breaks option further customizes line break behavior. In standard CommonMark, a single line break within a paragraph is treated as a space — you need two trailing spaces or a blank line to create a line break. Enabling Breaks mode converts every single \n into a <br> tag, which is useful for chat applications and comment systems where users expect line breaks to be preserved as typed.