How to Add Countdown Timer to Website (HTML & JS)

A countdown timer is an effective tool for creating urgency or tracking time until a specific event. This page provides a free, customizable generator to help you add a countdown timer to a website using clean HTML, CSS, and JavaScript.

This utility is part of our suite of web tools. If you are planning event dates, you may find our Day of the Week Calculator helpful. For design customization, use our Color Code Converter to match hex and RGB values. We also offer a Quick QR Code Generator for sharing links easily.

Configuration

Live Preview

The timer below is updating in real-time based on your settings.

Generated Code

Copy the code below and paste it where you want the timer to appear on your webpage.

How the Code Works

The generated code relies on the JavaScript Date object and the setInterval function.

1. Calculating the Distance

We convert your target date into milliseconds. Every second, the script calculates the difference between that target time and the current time (now).

2. The Calculation Formula

Once we have the difference in milliseconds, we use modular arithmetic to break it down:

• Days: Math.floor(distance / (1000 * 60 * 60 * 24))
• Hours: Remainder divided by milliseconds in an hour.
• Minutes: Remainder divided by milliseconds in a minute.
• Seconds: Remainder divided by 1000.

Frequently Asked Questions