JavaScript Program to Find the Square Root

In this example, you'll learn to write a program to find the square root of a number in JavaScript.

To understand this example, you should have the knowledge of the following JavaScript programming topics:


To find the square root of a number in JavaScript, you can use the built-in Math.sqrt() method. Its syntax is:

Math.sqrt(number);

Here, the Math.sqrt() method takes a number and returns its square root.


Example: Square Root of a Number

// take the input from the user
let number = prompt('Enter the number: ');

let result = Math.sqrt(number);
console.log(`The square root of ${number} is ${result}`);

Output

Enter the number: 9 
The square root of 9 is 3

Example 2: Square Root of Different Data Types

let number1 = 2.25;
let number2 = -4;
let number3 = 'hello';

let result1 = Math.sqrt(number1);
let result2 = Math.sqrt(number2);
let result3 = Math.sqrt(number3);

console.log(`The square root of ${number1} is ${result1}`);
console.log(`The square root of ${number2} is ${result2}`);
console.log(`The square root of ${number3} is ${result3}`);

Output

The square root of 2.25 is 1.5
The square root of -4 is NaN
The square root of hello is NaN
  • If a number is passed in the Math.sqrt() method, then the square root of that number is returned.
  • If a negative number is passed, NaN is returned.
  • If a string is passed, NaN is returned.