December 4, 2022

How to Set Decimal Precision in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to set decimal precision in javascript. It is very likely that there will be a large number of digits after the decimal point when we carry out a certain computation and return a decimal value. In order to make a number more readable, it is therefore quite standard practice to round it to a certain number of decimal places. For a newbie developer, it can be a bit tricky to set decimal precision.

There are numerous ways to set decimal precision. 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 set decimal precision 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 2 as a parameter. As a result, it will set the number to 2 decimal places.
We will display the result in the h1 element.

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

let num = 54251.2460223;

btnGet.addEventListener('click', () => {
    result.innerText = num.toFixed(2);
});

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