# How to Find Square Root in Javascript

In this tutorial, you will learn **how to find square root in javascript**. The square root is the number which when multiplied by itself, gives the original number. For example, 3 is the square root of 9, as 3 × 3 = 9.

Calculating the square root can be tricky if the value is coming from an input field because the value present in the input field is of string type. So first, we have to convert it into a number type using the `Number()`

method and then do the calculation.

To calculate a square root of a number, we can make use of the `Math`

object. This object contains a lot of methods and properties which can help us in various mathematical operations such as square root. This object contains the `sqrt()`

method which will take a number as a parameter and returns its square root.

In the following example, we have an input field in which we will enter a random number. Upon click of a button, we will get its square root and display that on the screen. Please have a look over the **code example** and the steps given below.

**HTML & CSS**

- We have 4 elements in the HTML file (
`div`

,`input`

,`button`

, and`h1`

). The`div`

element with a class of`container`

is just a wrapper for the rest of the elements. - The
`innerText`

for the`button`

element is`“Square Root”`

and for the`h1`

element, it is`“Result”`

. - We have done some basic styling using CSS and added the link to our
`style.css`

stylesheet inside the`head`

element. - We have also included our javascript file
`script.js`

with a`script`

tag at the bottom.

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <link rel="stylesheet" href="style.css"> <title>Document</title> </head> <body> <div class="container"> <input type="number" placeholder="Enter Number"> <button>Square Root</button> <h1>Result</h1> </div> <script src="script.js"></script> </body> </html>

.container { text-align: center; } button { margin-top: 10px; padding: 10px 20px; } input { display: block; margin: 10px auto; padding: 10px 20px; } input[type=number]::-webkit-inner-spin-button, input[type=number]::-webkit-outer-spin-button { -webkit-appearance: none; margin: 0; }

**Javascript**

- We have selected the
`input`

element,`button`

element, and`h1`

element using the`document.querySelector()`

method and stored them in`input`

,`btnSqrt`

, and`output`

variables respectively. - We have attached a
`click`

event listener to the`button`

element. - In the event handler function, we are passing the value of the
`input`

element to the`Number()`

method and storing the number in the`num`

variable. - We are calling
`sqrt()`

method to get the square root of`num`

and storing it in the`result`

variable. - We only want the
`result`

to be up to 2 decimal places and that is why we are using the`toFixed()`

method and passing 2 as a parameter. - We are displaying the
`result`

in the`h1`

element using the`innerText`

property.

let input = document.querySelector("input"); let btnSqrt = document.querySelector("button"); let output = document.querySelector("h1"); btnSqrt.addEventListener("click", () => { let num = Number(input.value); let result = Math.sqrt(num); result = result.toFixed(2); output.innerText = result; });