We're looking for a person or people to help audit MDN to find places we could speed up. Is this you or someone you know? Check out the RFP: https://mzl.la/2IHcMiE

The Number.isFinite() method determines whether the passed value is a finite number.




The value to be tested for finiteness.

Return value

A Boolean indicating whether or not the given value is a finite number.


In comparison to the global isFinite() function, this method doesn't forcibly convert the parameter to a number. This means only values of the type number, that are also finite, return true.


Number.isFinite(Infinity);  // false
Number.isFinite(NaN);       // false
Number.isFinite(-Infinity); // false

Number.isFinite(0);         // true
Number.isFinite(2e64);      // true

Number.isFinite('0');       // false, would've been true with
                            // global isFinite('0')
Number.isFinite(null);      // false, would've been true with
                            // global isFinite(null)


Number.isFinite = Number.isFinite || function(value) {
    return typeof value === 'number' && isFinite(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

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support19 Yes16 No159
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes16 Yes Yes ?

See also

Document Tags and Contributors

 Last updated by: roryokane,