The toString() method returns a string representing the specified Number object.




Optional. An integer between 2 and 36 specifying the base to use for representing numeric values.

Return value

A string representing the specified Number object.


If toString() is given a radix not between 2 and 36, a RangeError is thrown.


The Number object overrides the toString() method of the Object object; it does not inherit Object.prototype.toString(). For Number objects, the toString() method returns a string representation of the object in the specified radix.

The toString() method parses its first argument, and attempts to return a string representation in the specified radix (base). For radixes above 10, the letters of the alphabet indicate numerals greater than 9. For example, for hexadecimal numbers (base 16), a through f are used.

If the radix is not specified, the preferred radix is assumed to be 10.

If the numObj is negative, the sign is preserved. This is the case even if the radix is 2; the string returned is the positive binary representation of the numObj preceded by a - sign, not the two's complement of the numObj.

If the numObj is not a whole number, the 'dot' sign is used to separate the decimal places.


Using toString

var count = 10;

console.log(count.toString());    // displays '10'
console.log((17).toString());     // displays '17'
console.log((17.2).toString());   // displays '17.2'

var x = 6;

console.log(x.toString(2));       // displays '110'
console.log((254).toString(16));  // displays 'fe'

console.log((-10).toString(2));   // displays '-1010'
console.log((-0xff).toString(2)); // displays '-11111111'


Specification Status Comment
ECMAScript 1st Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.1.
ECMAScript 5.1 (ECMA-262)
The definition of 'Number.prototype.tostring' in that specification.
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number.prototype.tostring' in that specification.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Number.prototype.tostring' in that specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

JavaScript Method Number Prototype