Web/JavaScript/Reference/Operators/Exponentiation

The exponentiation operator (**) returns the result of raising the first operand to the power of the second operand. It is equivalent to Math.pow, except it also accepts BigInts as operands.

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Syntax

Operator: var1 ** var2

Description

The exponentiation operator is right-associative: a ** b ** c is equal to a ** (b ** c).

In most languages, such as PHP, Python, and others that have an exponentiation operator (**), the exponentiation operator is defined to have a higher precedence than unary operators, such as unary + and unary -, but there are a few exceptions. For example, in Bash, the ** operator is defined to have a lower precedence than unary operators.

In JavaScript, it is impossible to write an ambiguous exponentiation expression. That is, you cannot put a unary operator (+/-/~/!/delete/void/typeof) immediately before the base number; doing so will cause a SyntaxError.

-2 ** 2; 
// 4 in Bash, -4 in other languages. 
// This is invalid in JavaScript, as the operation is ambiguous. 


-(2 ** 2); 
// -4 in JavaScript and the author's intention is unambiguous.

Note that some programming languages use the caret symbol ^ for exponentiation, but JavaScript uses that symbol for the bitwise logical XOR operator.

Examples

Basic exponentiation

2 ** 3   // 8
3 ** 2   // 9
3 ** 2.5 // 15.588457268119896
10 ** -1 // 0.1
NaN ** 2 // NaN

Associativity

2 ** 3 ** 2   // 512
2 ** (3 ** 2) // 512
(2 ** 3) ** 2 // 64

Usage with unary operators

To invert the sign of the result of an exponentiation expression:

-(2 ** 2) // -4

To force the base of an exponentiation expression to be a negative number:

(-2) ** 2 // 4

Specifications

Specification

ECMAScript (ECMA-262)The definition of 'Exponentiation operator' 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
Exponentiation (`**`)	Chrome Full support 52	Edge Full support 14	Firefox Full support 52	IE No support No	Opera Full support 39	Safari Full support 10.1	WebView Android Full support 51	Chrome Android Full support 52	Firefox Android Full support 52	Opera Android Full support 41	Safari iOS Full support 10.3	Samsung Internet Android Full support 6.0	nodejs Full support 7.0.0 Full support 7.0.0 Full support 6.5.0 Disabled' Disabled' From version 6.5.0: this feature is behind the `--harmony` runtime flag.

Legend

Full support: Full support
No support: No support
User must explicitly enable this feature.': User must explicitly enable this feature.