/JavaScript

# Math.sqrt

The Math.sqrt() function returns the square root of a number, that is

$∀x≥0,Math.sqrt(x)=x=the uniquey≥0such thaty2=x\forall x \geq 0, \mathtt{Math.sqrt(x)} = \sqrt{x} = \text{the unique} \; y \geq 0 \; \text{such that} \; y^2 = x$

## Syntax

Math.sqrt(x)

### Parameters

x
A number.

### Return value

The square root of the given number. If the number is negative, NaN is returned.

## Description

If the value of x is negative, Math.sqrt() returns NaN.

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(9); // 3
Math.sqrt(2); // 1.414213562373095

Math.sqrt(1);  // 1
Math.sqrt(0);  // 0
Math.sqrt(-1); // NaN
Math.sqrt(-0); // -0


## Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
sqrt 1 12 1 3 3 1
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
sqrt 1 18 4 10.1 1 1.0
Server
Node.js
sqrt 0.1.100

## See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sqrt