nigauri

This plugin to insert “Estimated Reading Time” at the beginning of content.
<ul>
<li>Can choose “Minutes” or “Minutes and seconds”.</li>
<li>Can output in free format.</li>
<li>Can switch show/hide in Home, Front page, Post, and Page.</li>
<li>Support shortcode and tag.</li>
<li>If you want to translate this plugin, you put ‘.po’ and ‘.mo’ in ‘languages’ directory. Japanese language file is included in this plugin.</li>
</ul>

Insert Estimated Reading Time

This plugin to insert "Estimated Reading Time" at the beginning of content.

layerpoint

Let your readers know how much time the blog post will take for reading. This plugin creates an estimated reading time of your posts that is inserted above the content or by using a shortcode. Automatically updates the read time based on the updates the blog post recieves.
The plugin is completely customizable using the Dashboard Settings. You can activte or deactivate the plugin, style it with the default classes or add your own custom classes. You can also set an estimated number of words read per minute. You can additionally add extra content before and after the estimated reading time as per your needs.

LP Estimated Reading Time

Very Good

Displays an estimated reading time of your blog posts

Insert Estimated Reading Time vs LP Estimated Reading Time