October 6, 2022

How to Round a Number to 3 Decimal Places in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to round a number to 3 decimal places in javascript. When we perform a specific calculation and return a decimal value, it is extremely likely that there will be a number of digits following the decimal point. A number is routinely rounded to a certain number of decimal places to make it simpler to read. For a newbie developer, it can be a bit tricky to round a number to 3 decimal places.

There are numerous ways to round a number to 3 decimal places. We are going to use the simplest approach which involves the usage of the toFixed() method. It converts the number to string and rounds it to a specified number of decimals.

In the following example, we have one global variable that holds a number. Upon click of a button, we will round a number to 3 decimal places and display the result on the screen. Please have a look over the code example and the steps given below.

HTML & CSS

We have 3 elements in the HTML file (div, button, and h1). The div element is just a wrapper for the rest of the elements.
The innerText for the button element is “Get”.
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>
        <button>Get</button>
        <h1>Result</h1>
    </div>
    
    <script src="script.js"></script>
</body>
</html>

body {
    text-align: center;
}

div {
    display: inline-block;
}

button{
    display:inline-block;
    padding: 10px 20px;
}

Javascript

We have selected 2 elements (button and h1) using the document.querySelector() method and stored them in btn and result variables.
We have created a global variable num that holds a decimal number as a value.
We have added a click event listener to the button element.
We are executing the toFixed() method and passing 3 as a parameter. As a result, it will round the number to 3 decimal places.
We will display the result in the h1 element.

let btnGet = document.querySelector('button');
let result = document.querySelector('h1');

let num = 141215.12553;

btnGet.addEventListener('click', () => {
    result.innerText = num.toFixed(3);
});

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