# How to Find Cube of a Number in Javascript

In this tutorial, you will learn how to find cube of a number in javascript. To get the cube of a number, we have to multiply the number by itself thrice. For example, the cube of 3 is 9, as 3 × 3 x 3 = 9.

Calculating the cube of a number can be tricky if the number 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 the cube 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. One of those methods is the `pow()` method which will take a base and an exponent as a parameter and returns a number representing the given base taken to the power of the given exponent.

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 cube 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 is just a wrapper for the rest of the elements.
• The `innerText` for the `button` element is `“Cube”` 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">

<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>

<body>

<div class="container">
<input type="number" placeholder="Enter Number">
<button>Cube</button>
<h1>Result</h1>
</div>

<script src="script.js"></script>
</body>

</html>```
```.container {
text-align: center;
}

button {
margin-top: 10px;
}

input {
display: block;
margin: 10px auto;
}

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`, `btnCb`, 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 the `pow()` method to get the cube of `num` and storing it in the `result` variable.
• We are displaying the `result` in the `h1` element using the `innerText` property.
```let input = document.querySelector("input");
let btnCb = document.querySelector("button");
let output = document.querySelector("h1");