Math.sqrt()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The Math.sqrt() static method returns the square root of a number. That is

\forall x \geq 0,\;\mathtt{\operatorname{Math.sqrt}(x)} = \sqrt{x} = \text{the unique } y \geq 0 \text{ such that } y^2 = x

Try it

function calcHypotenuse(a, b) {
  return Math.sqrt(a * a + b * b);
}

console.log(calcHypotenuse(3, 4));
// Expected output: 5

console.log(calcHypotenuse(5, 12));
// Expected output: 13

console.log(calcHypotenuse(0, 0));
// Expected output: 0

Syntax

Math.sqrt(x)

Parameters

x: A number greater than or equal to 0.

Return value

The square root of x, a nonnegative number. If x < 0, returns NaN.

Description

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

Examples

Using Math.sqrt()

Math.sqrt(-1); // NaN
Math.sqrt(-0); // -0
Math.sqrt(0); // 0
Math.sqrt(1); // 1
Math.sqrt(2); // 1.414213562373095
Math.sqrt(9); // 3
Math.sqrt(Infinity); // Infinity

Specifications

Specification
ECMAScript® 2026 Language Specification # sec-math.sqrt

Browser compatibility

	Desktop					Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`sqrt`	1	12	1	3	1	18	4	10.1	1	1.0	4.4	1.0	0.10.0