JavaScript (ES2026) reference · Number Methods and Properties

JavaScript Number.isFinite() Method

Return true if a value is a finite number. Unlike the global isFinite(), it doesn't convert strings.

JavaScript (ES2026) Since ES2015

Create a free account to save this page, take notes and track your progress. Sign in

Syntax

Number.isFinite(value)

Parameter	Description
`value`	The value to test.

true or false.

Finite numbersTry it yourself

console.log(Number.isFinite(42), Number.isFinite(Infinity), Number.isFinite(NaN));

Output

true false false

No type conversion, unlike the globalTry it yourself

console.log(Number.isFinite("42"), isFinite("42"));

Output

false true

Version	Change
JavaScript ES2015	Added

Number.isNaN() · Return true only if a value is the number NaN. Unlike the global isNaN(), it doesn't convert strings first.
isFinite() · Return true if a value is a finite number after converting it to a number. Prefer Number.isFinite() for strict checks.
JavaScript Numbers · tutorial
JavaScript Type Conversion · tutorial