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Format numbers in the user's locale using vanilla JS

JavaScript has a built-in language-sensitive number formatting feature, called Intl.NumberFormat. This is useful if you want to format large numbers, use thousand separators, format currency values. It is supported by all evergreen browsers, except Internet Explorer.


  const formatter = new Intl.NumberFormat('de-DE', { 
     style: 'currency', 
     currency: 'EUR' 

  // expected output: "123.456,79 €"
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The NumberFormat documentation on MDN is not very clear about the available options, so I decided to build a playground that allows you to customize the formatting options and immediately see the result for a list of locales and input numbers.

In the sidebar you'll find some presets that showcase interesting use cases.

Note: The features marked as V3 will be implemented in a future version of ECMAScript. Therefore, they may not yet be available in your browser yet. I will add a polyfill as soon as it is available.

Open the Codesandbox fullscreen for easy editing. The playground is built in React using the Mantine component library.

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