Web/JavaScript/Reference/Global objects/isFinite

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

Syntax

isFinite(testValue)

Parameters

testValue: 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.

Description

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.

Examples

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")

Specifications

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

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`isFinite`	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 4	Opera Full support 3	Safari Full support 1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0	nodejs Full support 0.1.100

Legend

Full support: Full support