List of HTML Self-Closing Tags

Here is a complete list of self-closing tags for HTML5. These are called void-elements in HTML spec.

• <area />
• <base />
• <br />
• <col />
• <embed />
• <hr />
• <img />
• <input />
• <link />
• <meta />
• <param />
• <source />
• <track />
• <wbr />

• <command /> (obsolete)
• <keygen /> (obsolete)
• <menuitem /> (obsolete)
• <frame /> (obsolete)

The space before the slash is optional.

Is the Ending Slash Optional?

• HTML5: the slash is optional.
• HTML4: the slash is technically invalid. However, it's accepted by W3C's HTML validator.
• XHTML: The slash is REQUIRED.

I recommend to always add the slash. Because, it provides a visual clue of non-closing tags.

XHTML Supports Self-Closing Syntax for All Tags

In XML/XHTML, any tag can be self-closed by the ending slash <… />.

When you test XML, you have to make sure the server is sending the correct Internet media type as XHTML (e.g. application/xhtml+xml), otherwise browsers will treat it as HTML, regardless of the DOCTYPE in your file.

Reference