Have you ever read an article on Medium.com?  Of course, you must have. 

Aren't these clean and fancy pages make reading a lot smoother? Also, You must have noticed the read time it provides for every article.

The below strategy is mentioned on MarketingLand

 Once a Front-end engineer Brian Cray added similar estimated reading times (ERT) to the articles on his site, which drastically improved his overall Time on Site (Reading Time) by 13.8%. He wrote, “people either followed me, subscribed to my blog, or retweeted my articles 66.7% more often.”

Wait !!!! It's good for small articles. But what happens if the article is long?

 If you're thinking that this might scare people away from longer posts, David Michael Ross found that it actually decreased his bounce rate on articles over 1,000 words by 13%. 

 Why does this happen?

Because people do want to get into more details and if they'll see the high ERT, they will probably save to read it later and might refer to your article again and again for deep insights. 

 Anyhow it increases the screen time and reduces bounce rate. If you want to apply it on your blog you can add it yourself by dividing the word count by an adult's average reading speed (approx 250 words per minute) or you can calculate ERT automatically by using tools like Read-O-Meter or WP Time to Read