The Number.isInteger() method determines whether the passed value is an integer.




The value to be tested for being an integer.

Return value

A Boolean indicating whether or not the given value is an integer.


If the target value is an integer, return true, otherwise return false. If the value is NaN or Infinity, return false. The method will also return true for floating point numbers that can be represented as integer.


Number.isInteger(0);         // true
Number.isInteger(1);         // true
Number.isInteger(-100000);   // true
Number.isInteger(99999999999999999999999); // true

Number.isInteger(0.1);       // false
Number.isInteger(Math.PI);   // false

Number.isInteger(NaN);       // false
Number.isInteger(Infinity);  // false
Number.isInteger(-Infinity); // false
Number.isInteger('10');      // false
Number.isInteger(true);      // false
Number.isInteger(false);     // false
Number.isInteger([1]);       // false

Number.isInteger(5.0);       // true
Number.isInteger(5.000000000000001); // false
Number.isInteger(5.0000000000000001); // true


Number.isInteger = Number.isInteger || function(value) {
  return typeof value === 'number' && 
    isFinite(value) && 
    Math.floor(value) === value;


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Number.isInteger' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Number.isInteger' in that specification.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
isIntegerChrome Full support YesEdge Full support 12Firefox Full support 16IE No support NoOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support 16Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yesnodejs Full support 0.12


Full support  
Full support
No support  
No support

See also

  • The Number object it belongs to.

Document Tags and Contributors

Last updated by: tushararora,