Reading Time is a small WordPress plugin that creates a progress bar that indicates how much you’ve scrolled on a website. It’s very useful to show the reading progress on page or a blog post. Generally, such indicators are used on long articles and help readers understand how far they are from finishing the article. It support most popular browsers: Chrome, Firefox, Safari, IE8+ and mobile browsers.

Demo: https://codecanyon.net/item/reading-time-reading-progress-bar-for-wordpress/19773718