https://github.com/words/flesch-kincaid
Formula to detect the grade level of text according to Flesch–Kincaid Grade Level (1975)
https://github.com/words/flesch-kincaid
ease readability reading
Last synced: 7 days ago
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Formula to detect the grade level of text according to Flesch–Kincaid Grade Level (1975)
- Host: GitHub
- URL: https://github.com/words/flesch-kincaid
- Owner: words
- License: mit
- Created: 2014-09-15T09:02:19.000Z (over 11 years ago)
- Default Branch: main
- Last Pushed: 2022-11-01T13:56:34.000Z (over 3 years ago)
- Last Synced: 2026-01-27T05:13:34.472Z (about 1 month ago)
- Topics: ease, readability, reading
- Language: JavaScript
- Homepage: https://wooorm.com/readability/
- Size: 56.6 KB
- Stars: 81
- Watchers: 5
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- Funding: funding.yml
- License: license
Awesome Lists containing this project
README
# flesch-kincaid
[![Build][build-badge]][build]
[![Coverage][coverage-badge]][coverage]
[![Downloads][downloads-badge]][downloads]
[![Size][size-badge]][size]
Formula to detect the grade level of text according to the [Flesch–Kincaid grade
level][formula].
## Contents
* [What is this?](#what-is-this)
* [When should I use this?](#when-should-i-use-this)
* [Install](#install)
* [Use](#use)
* [API](#api)
* [`fleschKincaid(counts)`](#fleschkincaidcounts)
* [Types](#types)
* [Compatibility](#compatibility)
* [Related](#related)
* [Contribute](#contribute)
* [Security](#security)
* [License](#license)
## What is this?
This package exposes an algorithm to detect ease of reading of English texts.
## When should I use this?
You’re probably dealing with natural language, and know you need this, if
you’re here!
This algorithm is based on syllables, whereas some others are not, which means
it’s tougher to get right and slower to calculate.
See [syllable][] for detecting syllables.
## Install
This package is [ESM only][esm].
In Node.js (version 14.14+, 16.0+), install with [npm][]:
```sh
npm install flesch-kincaid
```
In Deno with [`esm.sh`][esmsh]:
```js
import {fleschKincaid} from 'https://esm.sh/flesch-kincaid@2'
```
In browsers with [`esm.sh`][esmsh]:
```html
import {fleschKincaid} from 'https://esm.sh/flesch-kincaid@2?bundle'
```
## Use
```js
import {fleschKincaid} from 'flesch-kincaid'
// For “The Australian platypus is seemingly a hybrid of a mammal and reptilian
// creature.” (1 sentence, 13 words, 26 syllables).
fleschKincaid({sentence: 1, word: 13, syllable: 26})
// => 13.08
```
## API
This package exports the identifier `fleschKincaid`.
There is no default export.
### `fleschKincaid(counts)`
Given an object containing the number of words (`word`), the number of sentences
(`sentence`), and the number of syllables (`syllable`) in a document, returns
the U.S. grade level associated with the document.
##### `counts`
Counts from input document.
###### `counts.sentence`
Number of sentences (`number`, required).
###### `counts.word`
Number of words (`number`, required).
###### `counts.syllable`
Number of syllables (`number`, required).
##### Returns
Grade level associated with the document (`number`).
> 👉 **Note**: values can theoretically start at `-3.40` and end at `Infinity`.
## Types
This package is fully typed with [TypeScript][].
It exports the additional type `Counts`.
## Compatibility
This package is at least compatible with all maintained versions of Node.js.
As of now, that is Node.js 14.14+ and 16.0+.
It also works in Deno and modern browsers.
## Related
* [`automated-readability`](https://github.com/words/automated-readability)
— uses character count instead of error-prone syllable parser
* [`coleman-liau`](https://github.com/words/coleman-liau)
— uses letter count instead of an error-prone syllable parser
* [`dale-chall-formula`](https://github.com/words/dale-chall-formula)
— uses a dictionary; suited for higher reading levels
* [`flesch`](https://github.com/words/flesch)
— uses syllable count
* [`gunning-fog`](https://github.com/words/gunning-fog)
— uses syllable count, needs POS-tagging and NER
* [`smog-formula`](https://github.com/words/smog-formula)
— like `gunning-fog-index`, without needing advanced NLP
* [`spache-formula`](https://github.com/words/spache-formula)
— uses a dictionary, suited for lower reading levels
## Contribute
Yes please!
See [How to Contribute to Open Source][contribute].
## Security
This package is safe.
## License
[MIT][license] © [Titus Wormer][author]
[build-badge]: https://github.com/words/flesch-kincaid/workflows/main/badge.svg
[build]: https://github.com/words/flesch-kincaid/actions
[coverage-badge]: https://img.shields.io/codecov/c/github/words/flesch-kincaid.svg
[coverage]: https://codecov.io/github/words/flesch-kincaid
[downloads-badge]: https://img.shields.io/npm/dm/flesch-kincaid.svg
[downloads]: https://www.npmjs.com/package/flesch-kincaid
[size-badge]: https://img.shields.io/bundlephobia/minzip/flesch-kincaid.svg
[size]: https://bundlephobia.com/result?p=flesch-kincaid
[npm]: https://docs.npmjs.com/cli/install
[esm]: https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c
[esmsh]: https://esm.sh
[typescript]: https://www.typescriptlang.org
[contribute]: https://opensource.guide/how-to-contribute/
[license]: license
[author]: https://wooorm.com
[formula]: https://en.wikipedia.org/wiki/Flesch–Kincaid_readability_tests#Flesch–Kincaid_grade_level
[syllable]: https://github.com/words/syllable