Joeri van Veen

The reading progress bar is a great user experience on longreads. Especially if it accurately depicts the reading progress in the article text, and nothing else. This is standard on single blog posts and enabled by default.
Customization:
<ul>
<li>
Location top of screen, bottom of screen or below a sticky menu.
</li>
<li>
Choose color of the reading progress bar.
</li>
<li>
Have the bar start at 0% even when part of the article is visible.
</li>
<li>
Select post types you wish the bar to appear, or individual posts.
</li>
</ul>
Behaviour:
<ul>
<li>
The reading progress bar has smooth initializing since part of the text may already be visible, after that a lightweight update-function ensures quick response while scrolling.
</li>
<li>
The bar can attach itself to any (sticky) element that you define as an admin, when there are multiple, the first visible element will be used.
</li>
<li>
When there is no (longer a) visible element to attach to, the bar displays at the top.
</li>
<li>
If there is no single article identified (by class names or id) it uses the whole page to calculate progress.
</li>
</ul>
Estimated reading time (beta)
Since 1.6.0 this plugin has rudimentary estimated reading time functionality, for when your theme does not support it out of the box. 
There are some potential issues, some of which cannot be fixed in a plugin. If it does not work for you, switch it off. It will have no effect on the plugin then.
This is my 6th WordPress plugin but my first one freely available to everybody. I hope you enjoy using it as much as I enjoy building it!
Regards, 
Joeri

WP Reading Progress

Light weight fully customizable reading progress bar. Sticks to top, bottom or sticky menu, with fallback for small screens. Includes ert (beta).

Anton

The Estimated Reading Time Content plugin automatically calculates and displays the estimated time required to read your posts and pages. It enhances user experience by informing readers about the content length, encouraging engagement and readability.
Features:
<ul>
<li>Automatically displays reading time at the top or bottom of posts and pages.</li>
<li>Customizable words per minute for accurate reading time calculation.</li>
<li>Allows customization of the reading time text, font size, font color, and background color.</li>
<li>Provides a shortcode for inserting reading time in specific locations.</li>
<li>Includes a widget for displaying reading time in sidebars.</li>
<li>Admin settings page for easy configuration.</li>
</ul>
Key Benefits:
<ul>
<li>Improves user engagement by setting reading expectations.</li>
<li>Enhances content readability and planning.</li>
<li>Easy to customize to match your site’s design.</li>
</ul>
<h3>Usage</h3>
Once activated, the plugin will automatically display the reading time on all posts and pages based on your settings.
Shortcode:
You can also manually insert the reading time using the shortcode <code>[ertc_reading_time]</code> within your post or page content.
Examples:
<ul>
<li>
To display the reading time within the content:
<pre><code> This is the content of your post. [ertc_reading_time] ``
</code></pre>
</li>
<li>
To display the reading time for a specific post or page by ID:
<pre><code> [ertc_reading_time id="123"] ``
</code></pre>
</li>
</ul>
Widget:
Add the Estimated Reading Time widget to your sidebar or any widget area to display the reading time.

Estimated Reading Time Content

Adds a reading time block to posts and pages, with customizable settings and widget support.

WP Reading Progress vs Estimated Reading Time Content