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


Number.parseInt(string,[ radix])


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.


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


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.


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

Browser compatibility

BCD tables only load in the browser

See also