The core difference
HTML wraps content in tags: <h1>Title</h1>, <p>Text</p>. Markdown uses light punctuation: # Title, then a blank line, then the paragraph. The HTML is explicit and infinitely expressive; the Markdown is terse and far easier to type. One is a rendering format, the other a writing format that converts into it.
Readability in source form
Open an HTML file and you wade through angle brackets to find a sentence. Open a Markdown file and it reads almost like plain prose — a heading is a line starting with a hash, a list is a line starting with a dash. For documents that people edit by hand, that readability is the whole point.
Control and expressiveness
HTML can express anything a browser can render: custom attributes, embedded scripts, precise classes and structure beyond headings and lists. Markdown deliberately cannot. When you need fine control over markup, semantic attributes or interactive elements, HTML is the tool. When you need readable, portable text, Markdown wins.
Where each format is used
- Markdown: READMEs, documentation, notes, blog drafts, static site content, chat and issue comments
- HTML: full web pages, email templates, embedded widgets, anything needing exact structure or styling
- Both: documentation pipelines often write in Markdown and convert to HTML at build time
Converting between them
Markdown converts to HTML cleanly and predictably — every heading, list and code block maps to a standard tag. The reverse direction is less exact, because HTML can contain structure Markdown cannot express; converters drop or approximate those parts. In practice most teams standardise on Markdown as the source of truth and generate HTML on demand.