Markdown to HTML Converter with Preview
Convert supported Markdown syntax to HTML and inspect the rendered preview. Copy the HTML when it matches the destination's needs.
Markdown to HTML Converter
Convert Markdown into clean HTML — with all the essentials:
Lists work
- Free
- Fast
- Client-side
- Step one
- Step two
- Step three
Code formatting
Inline code and fenced blocks:
function hello(name) {
return `Hello, ${name}!`;
}Links & images
Visit our JSON Formatter.
Quotes & rules
Markdown is plain-text formatting designed for both reading and editing.
GFM extras
strikethrough and tables:
| Tool | Category | Free |
|---|---|---|
| JSON Formatter | Developer | Yes |
| CSS Filter | Design | Yes |
| HMAC Generator | Developer | Yes |
Inline HTML in the Markdown input is escaped, not rendered. The converter is focused on safe text-to-HTML translation — paste output directly into a CMS or template.
CommonMark + GFM
All CommonMark essentials (headings, bold/italic, code, links, images, lists, blockquotes, hr) plus GFM strikethrough, fenced code with language hint, and tables.
Live Rendered Preview
Side-by-side raw-HTML and rendered-preview tabs so you can verify the visual output matches your intent before pasting elsewhere.
Clean, Embed-Ready HTML
Output uses standard semantic elements (h1-h6, p, ul/ol/li, pre/code with language class, blockquote, hr, table) — paste into any CMS or template without modification.
100% Client-Side
Custom Markdown parser runs entirely in your browser. Inline HTML in input is escaped, not executed. No fetch, works offline once loaded.
Convert Markdown to clean, semantic HTML
Convert supported Markdown syntax to HTML and inspect the rendered preview. Copy the HTML when it matches the destination's needs. Markdown dialects differ, and a preview does not prove that another renderer supports the same extensions. Inspect links and generated markup before publishing. When accepting untrusted Markdown in an application, apply the appropriate rendering and sanitization policy there.
How to use the Markdown to HTML converter
- Paste or type your Markdown into the input box, or load the bundled sample to see the syntax in action.
- Read the rendered preview tab to confirm headings, lists, code, and tables look the way you intend.
- Switch to the raw HTML tab to inspect the exact tags you will be embedding — semantic
<h1>–<h6>,<p>,<ul>/<ol>,<pre><code>, and more. - Press Copy to send the converted HTML to your clipboard.
- Paste into your CMS block editor, email template, or static-site layout. Run it through the HTML formatter first if your target system is whitespace-picky.
What is Markdown, and how does conversion work?
Markdown is a plain-text formatting syntax that maps readable shorthand to HTML. The widely adopted baseline is CommonMark, an unambiguous spec that defines the core constructs: headings, paragraphs, lists, links, images, emphasis, code, and blockquotes. GitHub Flavored Markdown (GFM) is a strict superset that adds tables, task lists, strikethrough, and extended autolinks on top. This tool implements the CommonMark essentials plus three of the most-used GFM extensions: strikethrough, fenced code with a language hint, and pipe tables.
The parser walks your input line by line. It first lifts fenced code blocks out so their contents are never reinterpreted, escapes every <, >, &, ", and ' to its HTML entity, then applies inline transforms for bold, italic, code, links, images, and strikethrough. Block-level state tracks open lists, blockquotes, and tables until a blank line closes them. The output is standard semantic HTML5 — screen-reader friendly and ready for any container you supply. For the full grammar, see the MDN HTML elements reference.
"GFM is a strict superset of CommonMark. All the features which are supported in GitHub user content and that are not specified on the original Markdown syntax follow the GFM spec."— GitHub Flavored Markdown Spec, github.github.com/gfm
Worked examples: Markdown → HTML
Heading + emphasis
# Title with **bold**
<h1>Title with <strong>bold</strong></h1>
Fenced code with language hint
```js…```
<pre><code class="language-js">…</code></pre>
Escaped inline HTML (XSS-safe)
Run <script>alert(1)</script>
<p>Run <script>alert(1)</script></p>
Edge case · intra-word underscores
my_variable_name stays literal — underscore emphasis only fires when the underscore is not bordered by word characters, so identifiers and __dunder__ names are never italicized. This matches the CommonMark intra-word emphasis rule and is the one case most quick regex converters break. Use *italic* next to letters.
Supported Markdown syntax reference
| Markdown syntax | HTML output | Notes |
|---|---|---|
| # Heading 1 … ###### Heading 6 | <h1>…<h6> | Six levels; space required after the #. ATX-style. |
| **bold** or __bold__ | <strong> | Both asterisk and underscore syntaxes accepted. |
| *italic* or _italic_ | <em> | Single asterisk or underscore. |
| `inline code` | <code> | Single backticks. Use double backticks if the code contains a backtick. |
| ```lang\n…\n``` | <pre><code> | Fenced code block with optional language hint. |
| [text](url "title") | <a href="…" title="…"> | Inline link. Title attribute optional. |
|  | <img alt="…" src="…"> | Inline image. Alt text required for accessibility. |
| - item / * item / + item | <ul><li> | Unordered list. Any of three bullet characters. |
| 1. item / 2. item | <ol><li> | Ordered list. Number does not affect rendering. |
| > quote | <blockquote> | Quote block. Stack > for nesting. |
| --- or *** or ___ | <hr> | Horizontal rule. Three or more characters on a line by themselves. |
| ~~strikethrough~~ (GFM) | <del> | GitHub Flavored Markdown — not in original CommonMark. |
| | col | col | (GFM) | <table> | GFM tables; header row + divider (---|---) on the next line. |
Not supported: setext headings, nested lists, reference-style links, definition lists, footnotes, task-list checkboxes, raw HTML pass-through. For those, use a full library like markdown-it or marked.
The conversion limits most tools hide
This is a focused parser, not a full CommonMark conformance engine, so a few real edge cases are worth knowing before you ship the output. GFM table alignment colons in the divider row (:---, :---:, ---:) are parsed but ignored — the <table> is built without any text-align style, so add CSS yourself if you need column alignment. The fenced-code language token only captures word characters, so c++ and c# hints drop their trailing symbols and emit class="language-c".
Nested lists flatten — markers are matched only at the start of a line, so indented sub-items become siblings rather than a nested <ul>. And inline ~~strikethrough~~ is GFM, not original Markdown, so it will not render in stricter CommonMark-only parsers downstream. Every other inline and block element produces balanced, well-formed tags ready to embed.
Where Markdown-to-HTML conversion pays off
Embed Markdown content in a CMS
Convert your README or knowledge-base article into HTML you can paste into any rich-text or block editor.
Generate static-site HTML
Build a tiny static-site pipeline: write content in Markdown, convert to HTML, drop into your template.
Email-friendly newsletters
Compose newsletters in Markdown for legibility, then convert to inline HTML for email clients that need it.
Code documentation
Turn a code-heavy README into clean HTML with syntax-highlighting-ready <code class="language-xxx"> blocks.
Custom Markdown previews
Power Markdown previews in your own apps without bundling a heavyweight library.
Writing the source first? Use the Markdown editor for live, split-pane authoring, build tables with the Markdown table generator, and add navigation with the Markdown table-of-contents generator. For a full primer on the syntax, read our Markdown syntax guide.
Related text & content tools
Live split-pane writing with preview
Markdown Table GeneratorBuild pipe tables without typing pipes
Markdown TOCGenerate a linked table of contents
HTML FormatterBeautify the converted HTML output
HTML Entity ConverterEscape or unescape special characters
Word CounterCount words, characters & reading time
Case ConverterSwitch headings to title or sentence case
Find & ReplaceBulk-edit text before converting
Text SorterAlphabetize list items and lines
URL Slug GeneratorTurn a heading into a clean URL slug
Lorem Ipsum GeneratorPlaceholder text for layouts
Guide: Markdown SyntaxRead the full Markdown syntax guide
Guide: Text Tools for CreatorsRead the text-processing workflow guide
All ToolsBrowse the full Toolk toolbox
Last updated: September 15, 2026 · Runs 100% in your browser — no uploads, tool input is not sent to Toolk.
Frequently asked questions
Why does pasted raw HTML show as text instead of rendering?
By design. The converter escapes <, >, and & before any Markdown processing, so a pasted <script> tag comes out as visible, harmless text rather than executable markup. That single behavior makes the output safe to drop into a page without a sanitizer pass.
Do GFM table alignment colons survive conversion?
Partially — pipe tables convert into full <table> elements, but the alignment colons in the divider row are ignored, so no text-align styles are emitted. Add a small CSS rule targeting the generated table when columns must align left, center, or right.
Which syntax extensions are supported beyond CommonMark?
Strikethrough with double tildes, fenced code blocks with language hints for CSS class names, and GFM pipe tables. Autolinks, task lists, and footnotes are not implemented, so those constructs pass through as literal text in the output.
Is my document uploaded during conversion?
No. The parser is custom JavaScript running entirely in your tab — no fetch, no XHR, and Toolk’s page analytics do not receive your content. Watch DevTools while typing if you want proof; nothing is requested. It also works offline once loaded.
How do I clean up the HTML afterwards?
Paste the converted markup into Toolk’s HTML Formatter (/tools/html-formatter) to re-indent it for templates or code review — useful after converting long documents where every heading and paragraph lands on a single generated line.