# Footnotes Shortcode

> Adds a [ref] shortcode for footnotes: each note becomes a numbered superscript link, and all notes are listed at the end of the post with links back.

- Type: PHP
- Runs: Run everywhere
- Category: [Content](https://wpide.com/library/category/content/)
- Tags: shortcode, footnotes, references
- Author: WPIDE Team
- Installs: 0
- Updated: 2026-10-28
- Page: https://wpide.com/library/footnotes-shortcode/

## Code

```php
$wpide_footnotes = array();

add_shortcode( 'ref', function ( $atts, $content = '' ) use ( &$wpide_footnotes ) {
    $post_id = (int) get_the_ID();
    $content = trim( (string) $content );

    if ( '' === $content ) {
        return '';
    }

    $wpide_footnotes[ $post_id ][] = $content;
    $number = count( $wpide_footnotes[ $post_id ] );
    $id     = $post_id . '-' . $number;

    return '<sup class="wpide-fn-ref" id="fnref-' . esc_attr( $id ) . '"><a href="#fn-' . esc_attr( $id ) . '">' . $number . '</a></sup>';
} );

add_filter( 'the_content', function ( $content ) use ( &$wpide_footnotes ) {
    $post_id = (int) get_the_ID();

    if ( empty( $wpide_footnotes[ $post_id ] ) ) {
        return $content;
    }

    $html = '<ol class="wpide-footnotes" style="font-size:.9em;">';

    foreach ( $wpide_footnotes[ $post_id ] as $index => $note ) {
        $id    = $post_id . '-' . ( $index + 1 );
        $html .= '<li id="fn-' . esc_attr( $id ) . '">' . wp_kses_post( $note ) . ' <a href="#fnref-' . esc_attr( $id ) . '" aria-label="Back to the text">&#8617;</a></li>';
    }

    unset( $wpide_footnotes[ $post_id ] );

    return $content . '<hr class="wpide-footnotes-separator" />' . $html . '</ol>';
}, 12 );
```

## Notes

Example: The study found this.[ref]Smith, 2024, page 12.[/ref] Notes can contain links and basic formatting.

## How to use it

Install the free WPIDE plugin (https://wordpress.org/plugins/wpide/), find "Footnotes Shortcode" in its snippet library and add it in one click; or create a new PHP snippet in WPIDE (or any code snippets plugin) and paste the code above. More snippets: https://wpide.com/library/