This plugin adds a variable to the context of Pelican with an stimation of minutes for reading the article.
To use it you have to add the plugin name to the pelicanconf.py file.
PLUGINS=[ ... , 'readtime']
Then you can access the minutes variable to show on your article.html template.
{% if article.readtime %}
<div><b>Read in {{article.readtime.minutes}} min.</b></div>
{% endif %}