Markdown to HTML

What the Markdown to HTML Does

Paste Markdown and the matching HTML appears, ready to copy or download as output.html. It opens on a small example and re-renders on every keystroke, so you can watch the tags take shape.

Markdown is the plain-text format John Gruber introduced in 2004 to write structured text that converts cleanly to HTML. This tool does that conversion for the elements you reach for in a README, a comment or a note.

How It Works

It applies a set of text rules: lines beginning with # become heading tags h1 to h6, double-asterisks become bold (the strong tag), single asterisks become italic (em), backtick spans become inline code and triple-backtick blocks become a code block, the link and image syntaxes become anchor and image tags, and lines starting with a dash, asterisk or plus become items in a bullet list.

The input is HTML-escaped first, so any raw HTML you paste is shown as text rather than rendered — a deliberate safety choice. The output updates as you type.

Data source & conversion logic

There's no external data. The conversion follows Markdown's common conventions — the format John Gruber introduced in 2004, later given an unambiguous specification by CommonMark — applied in your browser as a set of text rules.

1. Step 1. Escape the input so any literal HTML is shown as text, not rendered.
2. Step 2. Convert headings (one to six # marks), then fenced and inline code.
3. Step 3. Convert bold, italic, images and links to their HTML tags.
4. Step 4. Turn lines starting with a dash, asterisk or plus into items in a bullet list.
5. Step 5. Wrap the remaining lines as paragraphs; copy the HTML or download output.html.

Privacy

The Markdown you paste is converted entirely in your browser — nothing is sent to a server.

Nothing is stored; the text is gone when you close the tab.

Technical Details

Standards & references

• Markdown (John Gruber, 2004) — the original plain-text-to-HTML conventions this converter follows for everyday elements.
• CommonMark — the 2014 unambiguous specification of Markdown and the reference for correct behaviour. This tool implements a common subset, not the full spec.
• GitHub Flavored Markdown — GitHub's popular extensions such as tables and task lists — not handled here, since they sit on top of core Markdown.

Accuracy & Limitations

It's a lightweight subset converter, not a CommonMark-conformant parser. The everyday elements convert correctly; tables (a GitHub extension), blockquotes, ordered and nested lists, horizontal rules and strikethrough don't.

Raw HTML in your Markdown is escaped and shown as text rather than passed through. That's safe, but it means you can't mix in hand-written HTML and have it render.

Lists become flat bullet lists; indentation for nesting isn't interpreted, and numbered lists aren't recognised.

For full CommonMark or GitHub-Flavored fidelity — tables, task lists, footnotes — use a dedicated CommonMark processor.

Real-World Use Cases

When to use it — and when not to

Need tables, task lists or strict CommonMark? Use a full CommonMark/GFM processor. Want to write and see the result side by side? Use the Markdown editor. Going the other way? Use HTML to Markdown.

Frequently Asked Questions

References

• Markdown — history and syntax (Wikipedia)
• CommonMark — a strongly-defined Markdown spec
• GitHub Flavored Markdown spec (tables extension)

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