JavaScript Number isFinite() method

Definition and usage

if the number is finiteNumber.isFinite() The method returns true.

Infinite (non-finite) numbers are Infinity,-Infinity or NaN.

otherwise returns false.

See also:

Global isFinite() method

Number.isInteger() method

Number.isSafeInteger() method

Example

Example 1

Is 123 finite?

Number.isFinite(123)

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Example 2

Number.isFinite("123")

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Example 3

Number.isFinite(+1.23)
Number.isFinite(-1.23)
Number.isFinite('2005/12/12')

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Example 4

Number.isFinite(5-2)
Number.isFinite(5/2)
Number.isFinite(0)
Number.isFinite(0/0)
Number.isFinite(Infinity)
Number.isFinite(-Infinity)
Number.isFinite(NaN)

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Syntax

Number.isFinite(value)

parameter

parameter description
value Required. The value to be tested.

return value

type description
Boolean value if the value is finite trueotherwise false.

Difference between isFinite() and Number.isFinite()

ifvalueif the number is finite isFinite() Returns true.

ifnumberif the number is finite Number.isFinite() Returns true.

In other words:isFinite() Convert the value to a number before testing.

Example

isFinite(123)	 	// Returns true

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Number.isFinite("123")	// Returns false

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Browser support

Number.isFinite() is an ECMAScript6 (ES6) feature.

All modern browsers support ES6 (JavaScript 2015):

Chrome Edge Firefox Safari Opera
Chrome Edge Firefox Safari Opera
supports supports supports supports supports

Internet Explorer 11 (or earlier versions) does not support Number.isFinite().