Reading time is the estimated duration needed to read a piece of text from start to finish. It is typically calculated based on an average reading speed of 200-250 words per minute for English text, or 400-600 characters per minute for Japanese. Medium was one of the triggers for its spread across blogs and news sites; the company published its calculation method in June 2014, assuming a speed of about 275 words per minute, faster than the guideline above.

The calculation method is straightforward: divide the total word count (or character count) by the reading speed per minute, then round up. Viewing time for images and code blocks can also be added; Medium's published method, for example, counts about 12 seconds for the first image and less for each subsequent one.

The purpose of displaying reading time is to let readers gauge the length before they start. When an article shows "about 3 min read," it is easier to decide whether to read it now even without a long stretch of free time. No published figures generalize how much the display changes reading behavior, so its effect is something to verify with your own site's measurements. For writers, an excessively long reading time is a signal to consider splitting the article or tightening its structure.

For implementation, there are two approaches: pre-calculating on the server side or dynamically computing with JavaScript on the client side. Static site generators typically calculate reading time at build time and embed it as metadata. WordPress offers plugins like Reading Time WP, Hugo has a built-in .ReadingTime page variable, and in Gatsby the gatsby-transformer-remark plugin provides timeToRead.

A common misconception is that reading time must be precise. In reality, reading speed varies greatly between individuals, and the estimate is merely a guideline. What matters more than accuracy is consistency: applying the same calculation standard across all articles on a site builds trust. Showing a shorter time than the real one to prompt readers to start is not advisable in the long run, because it betrays the expectations of readers who cannot finish.

In terms of character counting, reading time is a metric directly derived from character or word count. Combining a character counter tool with automatic reading time calculation allows writers to intuitively gauge article volume. No search engine has publicly stated that it uses the length of the estimate itself as a ranking signal, so the aim is to keep the volume within what readers can finish, not to pad or trim toward a particular minute count.