How to Add Tags in Obsidian Markdown: A Complete Guide

Tags in Obsidian are one of the simplest — and most powerful — ways to organize your notes without relying on rigid folder structures. Whether you're building a personal knowledge base, managing research, or tracking projects, understanding how tags work in Obsidian helps you connect ideas across your entire vault.

What Are Tags in Obsidian?

In Obsidian, tags are labels you attach to notes (or specific sections within notes) to group related content regardless of where it lives in your folder hierarchy. A note about "sleep habits" inside a Health folder can share a tag with a note about "productivity routines" inside a Work folder — because tags cut across structure.

Obsidian renders tags as clickable links. Click any tag and Obsidian opens a search showing every note in your vault that carries it.

The Two Ways to Add Tags in Obsidian Markdown

1. Inline Tags (In the Note Body)

The most direct method: type a hashtag followed immediately by a word, anywhere in the body of your note.

Rules for valid inline tags:

• No space between # and the tag name
• No special characters except hyphens (-), underscores (_), and forward slashes (/)
• Numbers are allowed, but a tag cannot be all numbers — #2024review works, #2024 does not
• Tags are case-insensitive in search, though Obsidian preserves the case you type

2. Frontmatter Tags (YAML Metadata)

Frontmatter sits at the very top of a note, enclosed in triple dashes. This is the preferred method when you want tags to be clean metadata rather than mixed into your prose.