How to Add Footnotes in Markdown

October 1, 20267 min read

A Markdown footnote has two halves. In the text you put a marker, [^1], right after the word it belongs to. Anywhere else in the file you write the note itself on its own line: [^1]: The note.. The marker turns into a small raised number that links down to the note, and every note is collected into a numbered list at the bottom of the page, wherever you wrote it in the file.

Footnotes are not part of CommonMark, the core Markdown spec. They are an extension, and GitHub, Obsidian and QuickMark each describe theirs a little differently. So instead of repeating the usual example, I ran 31 footnote cases through QuickMark's own renderer and wrote down what came out. Everything below is that output, not a reading of a spec.

The basic footnote

Arabica has less caffeine.[^1]

[^1]: Roughly 1.2% against 2.2%.

Three details matter:

• No space between the word and the marker is the usual style, but a space does no harm. caffeine [^1] still works.
• The colon after the label is required in the definition. The space after the colon is not: [^1]:Note works too.
• The definition can sit anywhere. Top of the file, under the paragraph, at the very end. The note always renders in the list at the bottom.

In QuickMark the raised number is a real link. Tap or click it and the page scrolls smoothly down to the note; the small ↩︎ arrow after the note scrolls you back to where you were reading. That works in the app on Mac, iPhone and iPad, and on pages you publish as a web link.

Name your footnotes, the numbers take care of themselves

The label inside [^…] does not have to be a number. It can be a word, and that is the better habit. [^source] tells you what the note is when you come back to the file in six months; [^7] tells you nothing.

Whatever you type, the reader sees numbers, and those numbers follow the order the markers appear in the text. Not the label, not the order of the definitions:

This is what makes footnotes painless to edit. Insert a new note at the top of a long document and every number below it shifts on its own. You never renumber anything by hand.

Labels: what breaks them

Labels are stricter than they look. These are the cases that surprised me:

The case-sensitive rule is worth remembering, because ordinary reference links in Markdown are not case-sensitive. [Link][Docs] finds [docs]: … just fine. Footnote labels do not get that kindness.

Using one footnote twice

Point at the same note from two places and you get one note with two back-links:

First claim.[^src] Second claim.[^src]

[^src]: Both come from the same report.

The second marker reads [1:1], meaning "note 1, second reference", so each of the two ↩︎ arrows can take you back to the right spot.

Inline footnotes: ^[like this]

For a quick aside you do not want to name, write the note right where it belongs, inside ^[ and ]:

Brew at 92 to 96 °C.^[Boiling water scorches the grounds.]

Inline notes get a number in the same sequence as the named ones, so you can mix both styles in one file, as the screenshot at the top does. Bold, links and even square brackets inside the note all survive.

Not every app reads this form. Obsidian documents it, with the caveat that it only renders in reading view. GitHub's footnote documentation does not list inline footnotes at all, so if a file is headed for a GitHub README, stick to [^label].

Longer notes: paragraphs, lists and code

A note can hold more than one line. How you continue it decides what you get:

That last row matters if you come from Obsidian. Its help page says to add 2 spaces at the start of each new line of a footnote. In QuickMark that works for lines that follow directly, but once there is a blank line between paragraphs you need 4 spaces. Four spaces work everywhere I tested, so that is the safe habit.

[^roast]: A rule of thumb, not a law.

    Grind size matters just as much.

What else works inside footnotes

A note is ordinary Markdown, so formatting carries over. In my tests these all rendered correctly inside a note: bold, inline code, links (external ones open in a new tab, like everywhere else), and KaTeX math such as $x^2$. A footnote inside another footnote works too: it simply becomes the next number.

Markers also work in headings and inside table cells.

One thing that is not a footnote: x^2^. QuickMark reads a caret pair as superscript, so that renders as x². The [^ opening bracket is what makes a footnote.

Footnotes when you export

Footnotes travel differently depending on the format:

• HTML and PDF keep the page as you see it in the preview: raised numbers in the text and the numbered note list at the end. See Markdown to HTML and Markdown to PDF.
• Word (.docx) does not produce native Word footnotes. I exported a test file and unzipped it: the markers come out as small superscript text and the notes become plain paragraphs at the end of the document, so Word's own footnote tools will not see them. If real Word footnotes matter for a paper, plan to convert them in Word afterwards. More on what survives in Markdown to Word.

Quick reference

For the rest of the syntax on one page, see the Markdown cheat sheet.

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