QuireWhat is an .md file?
Short answer: an .md file is a Markdown document. It is plain text, with simple symbols for formatting: # before a heading, - or * before a list item, **double asterisks** for bold. Any text editor opens it; a Markdown viewer shows it formatted.
Updated 15 October 2026.
Where Markdown came from
John Gruber released Markdown in 2004 as a “text-to-HTML conversion tool” for web writers. Its stated goal was to be as readable as possible, so a Markdown document can be published “as-is, as plain text” without looking like it is full of tags.
The original description left gaps, and tools filled them differently. CommonMark is a precise specification written to fix that, and GitHub Flavored Markdown builds on it, adding tables, task lists and strikethrough. When people say “Markdown” today, they usually mean something close to GitHub’s version.
Where you meet .md files
- README.md files, which GitHub and other code hosts show on a project’s front page.
- Documentation, CHANGELOG.md files and wikis.
- Notes apps such as Obsidian, which keep every note as an .md file.
- AI tools. Chatbots answer in Markdown, and coding agents such as Claude Code write their plans as .md files. See reading agent plan files.
- Google Docs, which since October 2026 can edit .md files without converting them.
You may also see the extensions .markdown, .mdown or .mkd. They are the same format.
How to open one
- Open it as text
Any text editor can open it: Notepad on Windows, TextEdit on a Mac, or a browser.
- Read it formatted
To turn the symbols into headings, lists and tables, open it in a Markdown viewer or editor, such as VS Code’s preview, Google Drive’s preview or a viewer extension in Chrome.
- Edit it if you need to
Change the text in any editor and save. It stays plain text, so nothing is lost.
Step-by-step guides for each system: Windows, Mac, Chromebook, and Chrome on any computer.
Is an .md file safe to open?
As text, yes: opening it in a text editor runs nothing. Markdown can contain HTML, though, and a renderer that displays that HTML as-is could run scripts or load images from other websites. Code hosts and careful viewers remove the risky parts before showing a file.
Quire Markdown is our extension, free on the Chrome Web Store. It opens .md files in Chrome and removes scripts, forms and embedded content. It doesn’t load images, which would tell their server that you opened the file. It never changes the original file.
Its limits: it opens UTF-8 text files up to 2 MB, images appear as blocked references, and diagrams and math aren’t drawn.
Questions
What does MD stand for?
In a file name, .md is short for Markdown.
Can I convert an .md file to Word or PDF?
Yes. See saving Markdown as a PDF. pandoc and Typora can also produce Word files.
Is a .md file the same as a .txt file?
Both are plain text. The .md extension tells apps that the text uses Markdown formatting, so they can show it formatted.