What Is Markdown? A Plain-English Explanation

Markdown is a lightweight markup language: you format plain text with simple symbols — # for a heading, ** for bold, - for a bullet point — and an app turns those symbols into formatted text. John Gruber created it in 2004 so that text written for the web would stay readable even before it is formatted. Today it is the native format of GitHub, Obsidian, Reddit, Discord, documentation sites and AI assistants such as ChatGPT and Claude, and Markdown files end in .md.

You write plain text. A Markdown renderer — built into GitHub, your notes app, a chat app or a converter — reads the symbols and displays the formatted version. The symbols were chosen to look like the way people already decorated plain-text email: asterisks around a word for emphasis, a dash at the start of a line for a list item, a > for quoted text.

Because the source is just text, it opens in any editor on any device, it is small, and it never depends on one company's file format. The trade-off is that you see the symbols while you write, unless your editor hides them.

• 2004 — the original. John Gruber published Markdown on his site Daring Fireball, with feedback from Aaron Swartz. It shipped as a syntax description plus a Perl script, Markdown.pl, that converted text to HTML.
• 2004–2014 — many dialects. The original description left edge cases open (how far to indent a nested list, what a blank line inside a list means), so each implementation filled the gaps differently. Sites added their own extras: tables, fenced code blocks, footnotes.
• 2014 — CommonMark. A group led by John MacFarlane (the author of Pandoc) published CommonMark, a precise specification with hundreds of test cases, so the same text renders the same way everywhere.
• 2016 — an official file type. RFC 7763 registered text/markdown as the media type for Markdown files.
• 2017 — GitHub Flavored Markdown (GFM). GitHub published its dialect as a strict superset of CommonMark that adds tables, task lists, strikethrough and automatic links. GFM is what most people mean by "Markdown" today, and it is what every example on this site follows.

The differences between dialects are covered in CommonMark vs GFM.

• Software and documentation: every GitHub and GitLab README, issue and pull request; documentation generators such as MkDocs, Docusaurus and Read the Docs; static site generators such as Hugo, Jekyll and Astro.
• Notes and writing apps: Obsidian, Logseq, Joplin, Bear, iA Writer and Typora store notes as .md files. Notion and Google Docs accept Markdown shortcuts as you type and can import and export it.
• Chat and forums: Discord, Reddit, Stack Overflow and Microsoft Teams format messages with Markdown. Slack and WhatsApp use their own Markdown-like syntax with different rules (see Markdown to Slack).
• Data science: text cells in Jupyter notebooks are Markdown.
• Books and e-readers: many authors write in Markdown and publish an EPUB with Markdown to EPUB.
• AI assistants: ChatGPT, Claude, Gemini and most other chatbots write their answers in Markdown, which the chat window renders as headings, lists and tables.

Language models are trained on huge amounts of text from the web, and much of the best-structured text — documentation, READMEs, Q&A sites — is written in Markdown. It gives a model a compact way to express structure (a heading, a numbered step, a table) using ordinary characters, and chat interfaces render it instantly.

The catch appears when you copy the raw text out of the chat, for example with a copy button or from an API response. You get the source, not the formatting: **bold** arrives as literal asterisks and ## as hash signs, and tables arrive as rows of pipes. That is why pasting into Word or an email often looks broken. Converting the Markdown fixes it:

• ChatGPT to Word turns an answer into a real .docx with headings, lists and tables.
• Markdown to Google Docs and Markdown to Email put formatted text on your clipboard.
• Remove asterisks from ChatGPT text strips the symbols when you only want clean plain text.

An .md file (sometimes .markdown) is a plain-text file written in Markdown. Nothing about it is proprietary: rename it to .txt and it opens in Notepad or TextEdit with the symbols visible.

• To read it formatted, open it in a Markdown app (VS Code's preview, Obsidian, GitHub) or a browser-based viewer. MarkdownPreview.net has a full guide on how to open an .md file on Windows, Mac, iPhone and Android.
• To share it with people who don't use Markdown, convert it: Markdown to Word, Markdown to PDF or Markdown to HTML.
• To create one from an existing document, convert the other way: Word to Markdown, PDF to Markdown or Google Docs to Markdown.

Many people use both: draft and store content in Markdown, then convert to Word or PDF when someone needs a formatted document. For how Markdown relates to the web's own markup language, see Markdown vs HTML.

1. Open any text editor and type a heading line that starts with # .
2. Add a paragraph, a list with - items and a word wrapped in **.
3. Preview it, or paste it into a converter such as Markdown to HTML to see exactly how it was interpreted.

The Learn Markdown tutorial walks through every element with live examples, and the Markdown cheat sheet keeps the syntax on one page.

Support ranges from full GitHub Flavored Markdown to a handful of shortcuts. Checked in October 2026.