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[3]{x} = \text{the unique} \; y \; \text{such that} \; y^3 = x




A number.

Return value

The cube root of the given number.


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).


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);  // 1.2599210498948734


For all x0x \geq 0, have x3=x1/3\sqrt[3]{x} = x^{1/3} so this can be emulated by the following function:

if (!Math.cbrt) {
  Math.cbrt = function(x) {
    var y = Math.pow(Math.abs(x), 1/3);
    return x < 0 ? -y : y;


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Math.cbrt' in that specification.
Standard Initial definition.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Math.cbrt' in that specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 38 25 (25) No support 25 7.1
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 25.0 (25) No support No support 8

See also

Document Tags and Contributors

 Last updated by: rwaldron,