How to Internationalize Numbers with JavaScript

By  on  

Presenting numbers in a readable format takes many forms, from visual charts to simply adding punctuation. Those punctuation, however, are different based on internationalization. Some countries use , for decimal, while others use .. Worried about having to code for all this madness? Don't -- JavaScript provides a method do the hard work for you!

The Number primitive has a toLocaleString method to do the basic formatting for you:

const price = 16601.91;

// Basic decimal format, no providing locale
// Uses locale provided by browser since none defined
price.toLocaleString(); // "16,601.91"

// Provide a specific locale
price.toLocaleString('de-DE'); // "16.601,91"

// Formatting currency is possible
price.toLocaleString('de-DE', { 
  style: 'currency', 
  currency: 'EUR' 
}); // "16.601,91 €"

// You can also use Intl.NumberFormat for formatting
new Intl.NumberFormat('en-US', {
  style: 'currency',
  currency: 'GBP'
}).format(price); // £16,601.91

It's a major relief that JavaScript provides us these type of helpers so that we don't need to rely on bloated third-party libraries. No excuses -- the tool is there!

Recent Features

  • By
    Create a CSS Cube

    CSS cubes really showcase what CSS has become over the years, evolving from simple color and dimension directives to a language capable of creating deep, creative visuals.  Add animation and you've got something really neat.  Unfortunately each CSS cube tutorial I've read is a bit...

  • By
    7 Essential JavaScript Functions

    I remember the early days of JavaScript where you needed a simple function for just about everything because the browser vendors implemented features differently, and not just edge features, basic features, like addEventListener and attachEvent.  Times have changed but there are still a few functions each developer should...

Incredible Demos

  • By
    Dynamic Waveform Visualizations with wavesurfer.js

    Waveform images are an awesome addition to boring audio widgets.  They can be functional as well as aesthetically pleasing, allowing users to navigate audio visually.  I recently found wavesurfer.js, an amazing waveform image utility that uses to Web Audio API to create super customizable...

  • By
    Adding Events to Adding Events in MooTools

    Note: This post has been updated. One of my huge web peeves is when an element has click events attached to it but the element doesn't sport the "pointer" cursor. I mean how the hell is the user supposed to know they can/should click on...

Discussion

  1. Simple usage without specifying a locale returns a formatted string in the default locale and with default options.

    const number = 3500;
    
    console.log(new Intl.NumberFormat().format(number));
    // '3,500' if in US English locale
    

    See more options with dashingarts.

  2. Is there any difference in the formatting between

    toLocaleString

    and format using

    new Intl.NumberFormat(...)

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!