Web/JavaScript/Reference/Global objects/Number/parseInt

The Number.parseInt() method parses a string argument and returns an integer of the specified radix or base.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

Number.parseInt(string,[ radix])

Parameters

string: The value to parse. If this argument is not a string, then it is converted to one using the ToString abstract operation. Leading whitespace in this argument is ignored.
radix Optional: An integer between 2 and 36 that represents the radix (the base in mathematical numeral systems) of the string. Be careful—this does not default to 10!

Return value

An integer parsed from the given string.

If the radix is smaller than 2 or bigger than 36, and the first non-whitespace character cannot be converted to a number, NaN is returned.

Polyfill

if (Number.parseInt === undefined) {
    Number.parseInt = window.parseInt
}

Examples

Number.parseInt vs parseInt

This method has the same functionality as the global parseInt() function:

Number.parseInt === parseInt // true

and is part of ECMAScript 2015 (its purpose is modularization of globals). Please see parseInt() for more detail and examples.

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'Number.parseInt' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`parseInt`	Chrome Full support 34	Edge Full support 12	Firefox Full support 25	IE No support No	Opera Full support 21	Safari Full support 9	WebView Android Full support ≤37	Chrome Android Full support 34	Firefox Android Full support 25	Opera Android Full support 21	Safari iOS Full support 9	Samsung Internet Android Full support 2.0	nodejs Full support 0.12

Legend

Full support: Full support
No support: No support