Number.isFinite()
Baseline
Widely available
This feature is well established and works across many devices and browser versions. Itâs been available across browsers since â¨September 2015â©.
The Number.isFinite() static method determines whether the passed value is a finite number â that is, it checks that a given value is a number, and the number is neither positive Infinity, negative Infinity, nor NaN.
Try it
console.log(Number.isFinite(1 / 0));
// Expected output: false
console.log(Number.isFinite(10 / 5));
// Expected output: true
console.log(Number.isFinite(0 / 0));
// Expected output: false
Syntax
js
Number.isFinite(value)
Parameters
value-
The value to be tested for finiteness.
Return value
The boolean value true if the given value is a finite number. Otherwise false.
Examples
Using isFinite()
js
Number.isFinite(Infinity); // false
Number.isFinite(NaN); // false
Number.isFinite(-Infinity); // false
Number.isFinite(0); // true
Number.isFinite(2e64); // true
Difference between Number.isFinite() and global isFinite()
In comparison to the global isFinite() function, this method doesn't first convert the parameter to a number. This means only values of the type number and are finite return true, and non-numbers always return false.
js
isFinite("0"); // true; coerced to number 0
Number.isFinite("0"); // false
isFinite(null); // true; coerced to number 0
Number.isFinite(null); // false
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-number.isfinite |