June 29, 2020

How to Convert Unix Timestamp to Universal Time in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to convert Unix timestamp to universal time in javascript. Unix timestamp is the number of seconds that’s have been passed since January 1st, 1970 at UTC. UTC stands for Universal Time Coordinated. Before 1972, it was known as Greenwich Mean Time.

Unix timestamp does not change no matter where you are located in the world. This makes it easy for the computer systems to convert universal time into your local time. In javascript, we are going to use the Date constructor to convert the Unix timestamp to universal time.

The following example is pretty straightforward. We have timestamp 10999285 and we will convert it into universal time. Please have a look over the code example and 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.
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 one global variable timestamp and assigned 10999285 as a value.
We have attached the click event listener to the button element.
Inside the click event handler, we are making use of the Date constructor. We are converting the timestamp in seconds to milliseconds by multiplying it by 1000 and supplying it to the Date constructor as a parameter. As a result, we are getting the date object which we are storing in dateObj variable.
We are using getUTCHours(), getUTCMinutes(), getUTCSeconds() functions to get hours, minutes, and seconds of universal time.
We are using padStart(2, 0) to make sure always 2 digits should be displayed on the screen. If we have only one digit, then we will prepend 0 to it.
We are simply creating a template string and displaying it on the screen inside the h1 element.

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

//07:21:25
let timestamp = 10999285;

btnGet.addEventListener('click', () => {
   let dateObj = new Date(timestamp * 1000); 

   let hours = dateObj.getUTCHours().toString().padStart(2,0);
   let minutes = dateObj.getUTCMinutes().toString().padStart(2,0);
   let seconds = dateObj.getUTCSeconds().toString().padStart(2,0);

   result.innerText = `${hours}:${minutes}:${seconds}`;
});

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