About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

num2words

Convert a number to a word representation.

Installation

npm install @stdlib/string-num2words

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).
• To use as a general utility for the command line, install the corresponding CLI package globally.

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var num2words = require( '@stdlib/string-num2words' );

num2words( value[, options] )

Converts a number to a word representation.

var out = num2words( 87 );
// returns 'eighty-seven'

out = num2words( 23101 );
// returns 'twenty-three thousand one hundred one'

out = num2words( 0.53 );
// returns 'zero point five three'

The function accepts the following options:

• lang: string indicating the language. Default: 'en'.

By default, the function returns a word representation of a number in English. To return a word representation of a number in a different language, set the lang option.

var out = num2words( 22, {
    'lang': 'de'
});
// returns 'zweiundzwanzig'

out = num2words( 0.53, {
    'lang': 'de'
});
// returns 'null Komma fünf drei'

Notes

• The following languages are supported:

  • en: English.
  • de: German.

Examples

var num2words = require( '@stdlib/string-num2words' );

var out = num2words( 29 );
// returns 'twenty-nine'

out = num2words( 113 );
// returns 'one hundred thirteen'

out = num2words( 13.52 );
// returns 'thirteen point five two'

out = num2words( 47, {
    'lang': 'de'
});
// returns 'siebenundvierzig'

---

CLI

Installation

To use as a general utility, install the CLI package globally

npm install -g @stdlib/string-num2words-cli

Usage

Usage: num2words [options] [<string>]

Options:

  -h,    --help                Print this message.
  -V,    --version             Print the package version.
         --split sep           Delimiter for stdin data. Default: '/\\r?\\n/'.
         --lang lang           Language. Default: 'en'.

Notes

• If the split separator is a regular expression, ensure that the split option is either properly escaped or enclosed in quotes.

  # Not escaped...
  $ echo -n $'15\n23' | num2words --split /\r?\n/
  
  # Escaped...
  $ echo -n $'15\n23' | num2words --split /\\r?\\n/

• The implementation ignores trailing delimiters.

Examples

$ num2words '10'
ten

To use as a standard stream,

$ echo -n '23' | num2words
twenty-three

By default, when used as a standard stream, the implementation assumes newline-delimited data. To specify an alternative delimiter, set the split option.

$ echo -n '10.3\t23.1' | num2words --split '\t'
ten point three
twenty-three point one

---

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

---

License

See LICENSE.

Copyright

Copyright © 2016-2025. The Stdlib Authors.