# Math.cbrt()

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The Math.cbrt() function returns the cube root of a number, that is

$Math.cbrt(x)=x3=the uniqueysuch thaty3=x\mathtt{Math.cbrt(x)} = \sqrt{x} = \text{the unique} \; y \; \text{such that} \; y^3 = x$

## Syntax

Math.cbrt(x)

x
A number.

### Return value

The cube root of the given number.

## Description

Because cbrt() is a static method of Math, you always use it as Math.cbrt(), rather than as a method of a Math object you created (Math is not a constructor).

## Examples

### Using Math.cbrt()

Math.cbrt(NaN); // NaN
Math.cbrt(-1); // -1
Math.cbrt(-0); // -0
Math.cbrt(-Infinity); // -Infinity
Math.cbrt(0); // 0
Math.cbrt(1); // 1
Math.cbrt(Infinity); // Infinity
Math.cbrt(null); // 0
Math.cbrt(2);  // 1.2599210498948732


## Polyfill

For all $x \geq 0$, have $\sqrt\left[3\right]\left\{x\right\} = x^\left\{1/3\right\}$ so this can be emulated by the following function:

if (!Math.cbrt) {
Math.cbrt = (function(pow) {
return function cbrt(x){
// ensure negative numbers remain negative:
return x < 0 ? -pow(-x, 1/3) : pow(x, 1/3);
};
})(Math.pow); // localize Math.pow to increase efficiency
}


## Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.cbrt' in that specification.
Standard Initial definition.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Math.cbrt' in that specification.
Draft

## 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 Chrome Full support 38 Edge Full support 12 Firefox Full support 25 IE No support No Opera Full support 25 Safari Full support 8 WebView Android Full support Yes Chrome Android Full support 38 Firefox Android Full support 25 Opera Android Full support Yes Safari iOS Full support 8 Samsung Internet Android Full support Yes nodejs Full support 0.12

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