JavaScript Math sqrt()

In this tutorial, you will learn about the JavaScript Math.sqrt() method with the help of examples.

The sqrt() method computes the square root of a specified number and returns it.


// square root of 4
let number = Math.sqrt(4);

// Output: 2

sqrt() Syntax

The syntax of the Math.sqrt() method is:


Here, sqrt() is a static method. Hence, we are accessing the method using the class name, Math.

sqrt() Parameter

The sqrt() method takes a single parameter:

  • number - value whose square root is to be calculated

sqrt() Return Value

The sqrt() method returns:

  • the square root of a given positive integer or decimal number
  • NaN (Not a Number) if the argument is non-numeric or negative

Example 1: JavaScript Math.sqrt()

// sqrt() with integer number let number1 = Math.sqrt(16);
// sqrt() with a floating number let number2 = Math.sqrt(144.64);
console.log(number2); // Output: // 4 // 12.026637102698325

Here, we have used the Math.sqrt() method to compute the square root of an integer value, 16 and a decimal value, 144.64.

Example 2: sqrt() with Negative Argument

// sqrt() with negative number let number = Math.sqrt(-324);
console.log(number); // Output: NaN

Mathematically, the square root of any negative number is an imaginary number. That is why the sqrt() method returns NaN as the output.

Example 3: sqrt() with Infinity Values

// sqrt() with positive infinity let number1 = Math.sqrt(Infinity);
console.log(number1); // Output: Infinity
// sqrt() with negative infinity let number2 = Math.sqrt(-Infinity);
console.log(number2); // Output: NaN

Example 4: sqrt() with Numeric String

// cbrt() with a decimal number let number1 = Math.cbrt("81");
console.log(number1); // Output: 4.326748710922225

In the above example, the Math.sqrt() method converts the numeric string "81" into a number and then computes its square root.

Example 5: sqrt() with Non-Numeric Argument

let string = "Harry";

// sqrt() with string as argument let number = Math.sqrt(string);
console.log(number); // Output: NaN

In the above example, we have tried to calculate the square root of the string "Harry". That's why we get NaN as the output.

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