Calculating the estimated reading time for blog articles: A tutorial

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12/23/2023 | Web Development | Estimated reading time : min.

If you want to give your readers additional guidance and show them roughly how much time they should plan to spend reading your post, giving them an estimated reading time is a handy feature. In this blog article, I'll show you how you can create this added value on your website with a simple piece of JavaScript, regardless of which content management system or technology you use.

What the JavaScript code does

This code calculates the estimated reading time based on the number of words in a text. We assume that an average reader reads around 200 words per minute. You can adjust this value to the reading habits of your target group if necessary.

Essentially, the code consists of two parts:

The calculation function (calculateReadingTime): This function takes a text string, counts the words and divides this number by the average reading speed. The result is rounded up to the nearest whole number to obtain the minutes of reading time.
The update function (updateReadingTime): Here, the actual text is retrieved from an element with the .news-text-wrap class. After the reading time has been calculated, it is displayed in an element with the class .estimated-reading-time_inner.

Integration of the code

To use this feature, you must follow these steps:

1. integrate JavaScript code

Insert the provided JavaScript code into a JavaScript file or integrate it directly into a <script> tag within your HTML document:

<script>
// Here is the JavaScript for calculating and displaying the reading time
</script>

2. Prepare HTML elements

Your article HTML should contain at least two elements: One for the text content and one in which the reading time is displayed. For example:

<div class="estimated-reading-time">
  Estimated reading time: <span class="estimated-reading-time_inner"></span> minutes
</div>
<div class="news-text-wrap">
  <!-- Here is the text of the article -->
</div>

3. Call up JavaScript code

Make sure that the updateReadingTime function is called as soon as the text content has been loaded. If you insert the code directly into the HTML document, this is done automatically at the end of the script.

Make adjustments

Adjusted reading speed: If you know that your readers read faster or slower, you can change the wordsPerMinute value accordingly.
Responsive display: Make sure that the reading time display also looks and works well on mobile devices.

Conclusion

Indicating an estimated reading time on your page is a simple but effective way to provide readers with an additional service and exude professionalism at the same time. This little JavaScript snippet can be used anywhere, regardless of the platform used.

The JavaScript code

document.addEventListener('DOMContentLoaded', function() {
  // Estimated reading time for blog articles
  // Calculates the estimated reading time based on the number of words
  function calculateReadingTime(text) {
    const wordsPerMinute = 200; // Average reading speed
    const words = text.trim().split(/\s+/).length; // Count the words
    const readingTime = Math.ceil(words / wordsPerMinute);
    return readingTime;
  }
  // Updates the display of the estimated reading time
  function updateReadingTime() {
    const newsTextWrap = document.querySelector('.news-text-wrap');
    // Checks if the element exists
    if (newsTextWrap) {
      const textContent = newsTextWrap.innerText;
      const readingTime = calculateReadingTime(textContent);
      const readingTimeDisplay = document.querySelector('.estimated-reading-time_inner');
      // Only updates if the target element exists
      if (readingTimeDisplay) {
        readingTimeDisplay.innerText = `${readingTime}`;
      }
    }
  }
  updateReadingTime();
});

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[Translate to English:] Wolfgang Wagner, TYPO3 Experte und Trainer

Hi, I'm Wolfgang.

I have been working with TYPO3 since 2006. Not in theory, but in real projects with real deadlines. I've probably had the problems you're having three times already.

At some point, I started putting my knowledge into video courses. Not because I like being in front of the camera, but because I kept hearing the same questions over and over again. There are now hundreds of videos. Every single one was the result of a specific question from a specific project.

What makes me different from a YouTube tutorial: I not only know the solution, but also the context. Why something works. When it doesn't work. And which mistakes you can avoid because I've already made them.

As a member of the TYPO3 Education Committee, I make sure that the certification exams are kept up to date. What is tested there flows directly into my courses.