The global isFinite() function determines whether the passed value is a finite number. If  needed, the parameter is first converted to a number.




The value to be tested for finiteness.

Return value

false if the argument is (or will be coerced to) positive or negative Infinity or NaN or undefined; otherwise, true.


isFinite is a function property of the global object.

You can use this function to determine whether a number is a finite number. The isFinite function examines the number in its argument. If the argument is NaN, positive infinity, or negative infinity, this method returns false; otherwise, it returns true.


Using isFinite

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

isFinite(0);         // true
isFinite(2e64);      // true
isFinite(910);       // true

isFinite(null);      // true, would've been false with the 
                     // more robust Number.isFinite(null)

isFinite('0');       // true, would've been false with the 
                     // more robust Number.isFinite("0")


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

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
isFiniteChrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 4Opera Full support 3Safari Full support 1WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support 10.1Safari iOS Full support 1Samsung Internet Android Full support 1.0nodejs Full support 0.1.100


Full support  
Full support

See also