How to add the reading time of a post in WordPress without a plugin

Ready to use PHP snippet

Here you can find the entire snippet 👇

/**
* Estimated reading time in minutes
* 
* @param $content
* @param $words_per_minute
* @param $with_gutenberg
* 
* @return int estimated time in minutes
*/

function estimate_reading_time_in_minutes ( $content = '', $words_per_minute = 300, $with_gutenberg = false ) {
    // In case if content is build with gutenberg parse blocks
    if ( $with_gutenberg ) {
        $blocks = parse_blocks( $content );
        $contentHtml = '';

        foreach ( $blocks as $block ) {
            $contentHtml .= render_block( $block );
        }

        $content = $contentHtml;
    }
            
    // Remove HTML tags from string
    $content = wp_strip_all_tags( $content );
            
    // When content is empty return 0
    if ( !$content ) {
        return 0;
    }
            
    // Count words containing string
    $words_count = str_word_count( $content );
            
    // Calculate time for read all words and round
    $minutes = ceil( $words_count / $words_per_minute );
            
    return $minutes;
}

Line by line description of the custom PHP function

In the steps below we’ll describe the above code line by line:

1. At the beginning we conditionally process Gutenberg blocks into HTML code we can work with if required. More info is in the Usage of the function section at the end of this article

if ( $with_gutenberg ) {
    $blocks = parse_blocks( $content );
    $contentHtml = '';

    foreach ( $blocks as $block ) {
        $contentHtml .= render_block( $block );
    }

    $content = $contentHtml;
}

2. Then we want to remove all of the HTML tags from the content

$content = wp_strip_all_tags( $content );

3. After clearing all of the unnecessary characters we want to make sure that content is not empty

if ( !$content ) {
    return 0;
}

4. In the $words_count variable we want to count the number of words

$words_count = str_word_count( $content );

5. Finally we want to calculate the time needed to read the content assuming by default that we’re able to read 300 words per minute

$minutes = ceil( $words_count / $words_per_minute );

Usage of the function

You can use the function with 3 parameters:

Method 1: Basic usage

Counting time needed to read WordPress Blog Post

estimate_reading_timein_minutes( get_the_content() );

Method 2: Changing number of words per minute

By default, we assume that human is able to read 300 words per minute, but you can adjust that to your needs, ie. for some articles with hard words

estimate_reading_timein_minutes( get_the_content(), 200 );

Method 3: Assuming that content is based on the Gutenberg blocks

In many cases, you wouldn’t need to parse Gutenberg blocks. For example, if you call get_the_content() function in the page.php file WordPress will parse blocks for you, so you will get processed HTML code — in this case you should use $with_gutenberg param as false. However, if you use a custom function and you try to get post content by post ID, then you might want to set $with_gutenberg to true for process Gutenberg blocks into HTML:

estimate_reading_timein_minutes( get_the_content(), 200, true );

Summary

That’s it 🎉 If you have any thoughts about this snippet feel free to leave a comment or share this article in social media 😊