Math.sqrt

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

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

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

Specifications

Specification	Status	Comment
ECMAScript 1st Edition (ECMA-262)	Standard	Initial definition. Implemented in JavaScript 1.0.
ECMAScript 5.1 (ECMA-262) The definition of 'Math.sqrt' in that specification.	Standard
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Math.sqrt' in that specification.	Standard
ECMAScript 2017 Draft (ECMA-262) The definition of 'Math.sqrt' in that specification.	Draft

Browser compatibility

See also

• Math.cbrt()
• Math.exp()
• Math.log()
• Math.pow()