What is an MD file?

An MD file is a plain text file written in Markdown, a way of marking headings, lists and links with symbols such as # and *. The .md ending tells apps that the text is Markdown. Any text editor can open an MD file, and a Markdown viewer shows it formatted.

What is Markdown?

Markdown is a plain text format for writing structured documents. John Gruber developed it, with help from Aaron Swartz, and released it in 2004. A Markdown file stays easy to read as raw text, and apps that understand Markdown show it with real headings, bold text and lists.

What is a Markdown file?

A Markdown file's name ends in .md, or sometimes in the longer .markdown. Because the file is plain text, it has no hidden formatting and opens on any computer.

What the md format looks like

Here is a short Markdown file as you would see it in a text editor:

# Trip notes

Pack the **passport** and the *charger*.

- Train at 9:40
- Hotel: [booking page](https://example.com)

---

> Check out by 11:00.

In a Markdown viewer, the first line becomes a large heading and the dashes become a bulleted list. The double asterisks make bold text, single asterisks make italics, and the square and round brackets make a link. A --- line draws a horizontal rule, and a > line becomes a quote. The Markdown cheat sheet lists the rest of the Markdown format.

How to open an MD file

Most text editors show the raw Markdown, symbols included, which is fine for reading notes or making small changes. To read it formatted, use a Markdown viewer.

On Windows

Right-click the file, choose Open with, and pick Notepad, the text editor that comes with Windows.

On a Mac

Open TextEdit, choose File > Open and select the file.

On a phone or tablet

Open the MarkPrep Markdown viewer in your phone's browser and tap Open .md file. Pick the file from your downloads or files app, and it appears formatted below the text box.

Formatted, on any device

The Markdown viewer opens an .md file by button or drag-and-drop and shows it with headings, tables, highlighted code and a list of contents. Your browser reads the file, so it is never uploaded.

How to convert an MD file

To share a Markdown file with someone who doesn't use Markdown, convert it. Markdown to Word makes a .docx file with Word heading styles. Markdown to PDF prints it to a PDF, and Markdown to HTML makes a web page. To write or edit one first, use the Markdown editor.

You can also go the other way. MarkPrep turns a PDF into Markdown, a Word document into Markdown, and plain text into Markdown with TXT to Markdown. Each one lets you download the result as an .md file.