Quick Look Markdown on Mac: Preview .md in Finder

Short answer: Select a .md file in Finder and press the Space bar. What you see depends on the Quick Look extensions installed on your Mac. To get formatted Markdown, install an app with a Markdown Quick Look extension: QLMarkdown (free, open source), OpenMark (our app, which includes one), or PreviewMarkdown (Mac App Store).

Quick Look is the fastest way to check a file without opening an app. For a README, a CLAUDE.md or a set of meeting notes, one key press tells you whether it's the file you want. This guide covers how to preview Markdown with Quick Look, how three Markdown extensions compare, and what to check when the preview doesn't appear.

Disclosure: we make OpenMark, one of the three extensions compared here. The other two are made by independent developers, and every fact about them below comes from their own pages, checked on 2026-10-28.

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How to preview a .md file in Finder

Apple's Mac User Guide describes Quick Look like this: select one or more items, then press the Space bar.

1. Open the folder in Finder.
2. Click the .md file once to select it.
3. Press the Space bar. The Quick Look window opens.
4. Press Space again, or click the Close button, to close it.

You can select several files and press Space to step through them in one window.

What macOS shows without a Markdown extension

Apple's Quick Look page says it works on "nearly any kind of file", but it doesn't say anything about Markdown. A .md file is plain text. Whether you see the raw text or a formatted page depends on the apps and Quick Look extensions installed on your Mac, so I won't claim a specific default here. If you press Space and see ## and ** instead of headings and bold text, you don't have a Markdown extension installed (or it isn't turned on).

Quick Look can't format Markdown on its own. Apps add Quick Look extensions, and macOS lists them in System Settings. Apple describes them as extensions that "allow you to click on a file, then press spacebar to preview the file."

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The options compared

	QLMarkdown	OpenMark	PreviewMarkdown
What it is	Quick Look extension with a settings app	Markdown viewer and editor that includes a Quick Look extension	Quick Look previewer and thumbnailer
Price (as of 2026-10-28)	Free	$9.99 once (Mac + iPhone + iPad)	$2.99 (US Mac App Store)
Source	Open source, GPL-3.0	Closed source	Source on GitHub, MIT licence file
Install	GitHub releases or Homebrew	Mac App Store	Mac App Store
Tables	Yes (table extension)	Yes	Yes
Code blocks	Syntax highlighting	Monospace, no highlighting	Highlighted
Mermaid diagrams	Yes, when enabled	Shown as source	Not listed on its page
Math	MathJax, when enabled	Shown as raw LaTeX	Not listed on its page

QLMarkdown

QLMarkdown is the extension most people mean when they search "qlmarkdown" or "quick look markdown". It's free and open source under the GPL-3.0 licence, and it's actively released: version 1.5.7 came out on 2026-10-02, after four other releases since 11 September.

Install: download the app from the repo's releases page, or use Homebrew:

brew install --cask qlmarkdown

The README says the precompiled app is notarized and signed, and that you must launch the app at least once so macOS finds the extension.

What it renders: it's built on cmark-gfm (GitHub's Markdown engine) with optional extensions you turn on in its settings app: tables, syntax highlighting, emoji shortcodes, a table-of-contents sidebar, YAML headers, math with MathJax and Mermaid diagrams. For math and Mermaid, you choose whether the JavaScript library loads from a CDN (needs an internet connection) or is embedded in the preview. It also previews R Markdown (.rmd), Quarto (.qmd), MDX (without rendering JSX) and a few other formats.

Limits: the README says plainly that QLMarkdown "is not intended to be used as a standalone markdown file editor or viewer." It doesn't appear in Open With and won't open on double-click. It previews files; it doesn't open them.

Pick QLMarkdown if you want a free preview with diagrams and math, and you're happy to set it up once.

OpenMark's built-in Quick Look extension

OpenMark is a native Mac app for reading and editing Markdown, and it includes a Quick Look extension. Once OpenMark is installed, select a .md file in Finder and press Space.

To be clear about what the preview does: it uses the same Markdown engine as the app, but runs no JavaScript. In the Quick Look window you get:

• headings, paragraphs, links, blockquotes and horizontal rules
• tables
• nested lists and task lists (checkboxes are shown, not clickable)
• GitHub-style alerts (> [!NOTE], > [!WARNING] and so on)
• code blocks in monospace, without syntax highlighting
• YAML frontmatter hidden rather than printed at the top
• wiki-style [[links]] shown as links (they don't navigate in the preview)
• light or dark, following your Mac's appearance

Mermaid diagrams appear as their source code in a styled block, and LaTeX math appears as raw LaTeX in monospace. To see diagrams and math rendered, open the file in OpenMark: Document view renders Mermaid (flowchart, sequence, class, Gantt, Kanban, pie, mindmap) and math with KaTeX, and highlights code in 30+ languages.

So on diagrams and math, QLMarkdown's preview does more than OpenMark's. What OpenMark adds is the app behind the preview: press Space to check the file, then open it to read it fully rendered, edit it in Markdown view (⌘⇧M), or export it to PDF or HTML. It works offline with no account, is about 8 MB, costs $9.99 once for Mac, iPhone and iPad, and requires macOS 26 or later on the Mac. If you want .md files to open in OpenMark when you double-click them, see how to set OpenMark as the default app.

Get OpenMark on the Mac App Store

PreviewMarkdown

PreviewMarkdown by Tony Smith gives you a Quick Look preview and Finder thumbnails for Markdown files. It's sold on the Mac App Store at $2.99 (US store, as of 2026-10-28). The listing shows version 2.5.0 and says it "Requires macOS 12.4 or later." The source is on GitHub with an MIT licence file.

Its page lists tables, highlighted code blocks, blockquotes and optional YAML front matter. It doesn't list math or Mermaid. You can also set fonts and colours for the preview. As with QLMarkdown, you run the app once to register its extensions, and then you can quit it.

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Quick Look Markdown not working? What to check

1. Check the extension is turned on. Apple's Mac User Guide gives the path: choose Apple menu > System Settings, click General in the sidebar, then click Login Items & Extensions (you may need to scroll down). Then click the Info button next to Quick Look, turn the extension on, and click Done.

2. Launch the app once. QLMarkdown's README and PreviewMarkdown's page both say to run the app once after installing so macOS registers its extension. PreviewMarkdown's page also suggests logging out and back in if the extension still doesn't work.

3. Look for a conflict. Both developers say another app can claim the Markdown file type, and then a different extension handles the preview. QLMarkdown's README suggests turning off the other Quick Look extensions in that same settings list, checking that the preview works, then turning them back on one at a time to find the conflict.

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When Quick Look isn't enough

Quick Look is for a glance. If you need to read a long file, follow its outline or check a diagram, open it in a viewer. You have two options:

• No install: open or paste the file in our free online Markdown viewer, which runs in your browser.
• Other ways to open it: How to open an .md file on Mac covers TextEdit, Quick Look, VS Code, a viewer app and online options, with what each one shows.

If you want the Space-bar preview and a full Markdown app in one install, OpenMark is $9.99 on the Mac App Store.