An MD file is a plain-text document written in Markdown, and you can open it on Windows with any text editor, including Notepad. To see its headings, lists and links formatted, open it in an app with a Markdown view, such as Visual Studio Code or a recent version of Notepad on Windows 11.
Markdown marks formatting with ordinary characters: a line that starts with a hash sign is a heading, and a line that starts with a hyphen is a list item. That is why the file stays readable even without formatting.
What an MD file is
Markdown files end in .md, sometimes in .markdown. Both extensions are listed in RFC 7763, the document that registers the Markdown file type.
You find MD files in software projects, often as the README, in note apps that store notes as files, and in the output of converters. MD Factory, for example, creates MD files from PDF, Word and other documents on Windows.
When an AI chat such as Claude or ChatGPT gives you a document to download, it may also be an MD file. It is an ordinary Markdown file, and everything below applies to it.
Four ways to open an MD file
| App | What you see | Good for |
|---|---|---|
| Notepad | Plain text, or formatted Markdown in versions that support it | Quick reading and small edits |
| Visual Studio Code | The text with a live preview beside it | Editing long files |
| Obsidian or another Markdown editor | Formatted notes with links between them | Keeping your notes in Markdown |
| A web browser | Plain text, if the browser displays the file | A computer without other apps |
Notepad
Right-click the file, select Open with, then Notepad. Every version of Notepad shows the text. Recent versions on Windows 11 can also show it formatted.
Microsoft announced Markdown formatting in Notepad on May 30, 2025, in version 11.2504.52.0, and rolled it out to Windows Insiders first. Tables followed in version 11.2510.6.0, announced on November 21, 2025.
In a version with formatting, the View menu and a button in the status bar switch between formatted Markdown and Markdown syntax. To keep plain text, turn formatting off in Notepad's settings. Both options are described in Microsoft's announcement of text formatting in Notepad.
Visual Studio Code
Visual Studio Code is Microsoft's free code editor. Open the MD file in it and press Ctrl+Shift+V to switch to the preview, or Ctrl+K V to show the preview beside the text. The side preview updates as you type.
Microsoft lists both shortcuts in the Visual Studio Code documentation on Markdown.
Obsidian or another Markdown editor
Markdown editors show formatting as you write. Obsidian, for example, works with a folder of Markdown files called a vault. Copy the MD file into the vault folder, and it appears among your notes.
For PDF and Word documents, see how to import PDF and Word files into Obsidian.
A web browser
Drag the file into a browser window. If the browser displays it, you see the Markdown as plain text, without formatting. If it downloads the file instead, use one of the options above.
Choose the app that opens MD files
If no app is set for MD files, Windows asks which one to use each time. To make your choice permanent:
- Open Settings and go to Apps, then Default apps.
- In the search box, type
.mdand select the result. - Choose the app you want, such as Notepad or Visual Studio Code.
After that, a double-click opens every MD file in that app. Microsoft's guide to default apps describes the same steps for Windows 11 and Windows 10.
Markdown basics in one table
This is how the most common marks look in the file:
| To get | Type |
|---|---|
| A heading | # Title |
| A smaller heading | ## Section |
| Bold text | **important** |
| A bulleted list | - item |
| A numbered list | 1. item |
| A link | [text](https://example.com) |
| A table | | Name | Price | |
Headings, emphasis, lists and links are part of CommonMark, a specification of Markdown syntax. Tables are an extension from GitHub Flavored Markdown, so an app that sticks to plain CommonMark shows a table as plain text with vertical bars.
For more examples with their results, see GitHub's guide to basic formatting syntax.
Is it safe to open an MD file?
Opening an MD file in a text editor is safe: the file is plain text and does not run anything. RFC 7763 calls Markdown read as plain text "relatively harmless".
Links are a different matter. In a formatted view, a link in an MD file can lead to any website, and an image can be loaded from the internet. Treat links in a file from an unknown sender the way you treat links in an email: check where a link leads before you click it.
Also check that the file really ends in .md. If File Explorer hides file name extensions, a program named report.md.exe appears as report.md. To show extensions, select View, then Show, then File name extensions, as described in Microsoft's list of common file name extensions.