Build Coverage Downloads Size Sponsors Backers Chat

hast utility to estimate the reading time, taking readability of the document and a target age group into account.


This package is ESM only: Node 12+ is needed to use it and it must be imported instead of required.


npm install hast-util-reading-time


Say we have the following HTML from โ€œWord per minute: Alphanumeric entryโ€ on Wikipedia in example.html:

<p>Since the length or duration of words is clearly variable, for the purpose of measurement of text entry, the definition of each "word" is often standardized to be five characters or keystrokes long in English, including spaces and punctuation. For example, under such a method applied to plain English text the phrase "I run" counts as one word, but "rhinoceros" and "let's talk" would both count as two.</p>
<p>Karat et al. found that one study of average computer users in 1999, the average rate for transcription was 32.5 words per minute, and 19.0 words per minute for composition. In the same study, when the group was divided into "fast", "moderate", and "slow" groups, the average speeds were 40 wpm, 35 wpm, and 23 wpm, respectively.</p>
<p>With the onset of the era of desktop computers, fast typing skills became much more widespread.</p>
<p>An average professional typist types usually in speeds of 43 to 80 wpm, while some positions can require 80 to 95 (usually the minimum required for dispatch positions and other time-sensitive typing jobs), and some advanced typists work at speeds above 120 wpm. Two-finger typists, sometimes also referred to as "hunt and peck" typists, commonly reach sustained speeds of about 37 wpm for memorized text and 27 wpm when copying text, but in bursts may be able to reach much higher speeds. From the 1920s through the 1970s, typing speed (along with shorthand speed) was an important secretarial qualification and typing contests were popular and often publicized by typewriter companies as promotional tools.</p>

And our module, example.js:

import fs from 'node:fs'
import {unified} from 'unified'
import rehypeParse from 'rehype-parse'
import {readingTime} from 'hast-util-reading-time'

const example = fs.readFileSync('example.html')
const tree = unified().use(rehypeParse, {fragment: true}).parse(example)

  `It takes about ${Math.ceil(readingTime(tree, {age: 18}))}-${Math.ceil(readingTime(tree, {age: 14}))}m to read`

Now, running node example.js yields:

It takes about 2-3m to read


This package exports the following identifiers: readingTime. There is no default export.

readingTime(tree, options?)

Utility to estimate the reading time, taking readability of the document and a target age group into account.

The algorithm works as follows:

  • Estimate the WPM of the audience age based on the facts that English can be read at ยฑ228 WPM (Trauzettel-Klosinski), and that reading rate increases 14 WPM per grade (Carver)
  • Apply the readability algorithms Daleโ€”Chall, Automated Readability, Coleman-Liau, Flesch, Gunning-Fog, SMOG, and Spache
  • Adjust the WPM of the audience for whether the readability algorithms estimate its above or below their level
  • wordCount / adjustedWpm

Note: this algorithm is specific to English!


Target age group (number, default: 16). This is the age your target audience was still in school. Set it to 18 if you expect all readers to have finished high school, 21 if you expect your readers to all be college graduates, etc.


number โ€” Reading time in minutes. The resultโ€™s not rounded so itโ€™s possible to retrieve estimated seconds from it.


Use of hast-util-reading-time is safe.


See contributing.md in syntax-tree/.github for ways to get started. See support.md for ways to get help.

This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.


MIT ยฉ Titus Wormer

Hast Util Reading Time

utility to estimate the reading time

Hast Util Reading Time Info

โญ Stars55
๐Ÿ”— Homepageunifiedjs.com
๐Ÿ”— Source Codegithub.com
๐Ÿ•’ Last Updatea year ago
๐Ÿ•’ Createda year ago
๐Ÿž Open Issues0
โž— Star-Issue RatioInfinity
๐Ÿ˜Ž Authorsyntax-tree