# 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


## Specifications

Specification
ECMAScript (ECMA-262)
The definition of 'Math.sqrt' 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 Chrome Full support 1 Edge Full support 12 Firefox Full support 1 IE Full support 3 Opera Full support 3 Safari Full support 1 WebView Android Full support 1 Chrome Android Full support 18 Firefox Android Full support 4 Opera Android Full support 10.1 Safari iOS Full support 1 Samsung Internet Android Full support 1.0 nodejs Full support 0.1.100

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