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
    Vibration API

    Many of the new APIs provided to us by browser vendors are more targeted toward the mobile user than the desktop user.  One of those simple APIs the Vibration API.  The Vibration API allows developers to direct the device, using JavaScript, to vibrate in...

  • By
    Responsive and Infinitely Scalable JS Animations

    Back in late 2012 it was not easy to find open source projects using requestAnimationFrame() - this is the hook that allows Javascript code to synchronize with a web browser's native paint loop. Animations using this method can run at 60 fps and deliver fantastic...

Incredible Demos

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!