Quick Time Zones

How It Works

This digital clock uses your device’s system time and updates every second to show you the current time. The clock syncs with your operating system, which typically synchronizes with internet time servers to stay accurate within milliseconds.

When you select a different time zone, the clock calculates the offset from UTC (Coordinated Universal Time) and displays the corresponding local time:

For example, if it’s 12:00 UTC and you select Pacific Time (UTC-8 in winter), the clock shows 04:00. The system automatically handles daylight saving time changes for regions that observe it.

The 12-hour format adds AM/PM indicators, while 24-hour format (military time) runs from 00:00 to 23:59. Both formats show the same moment in time, just with different notation:

The clock refreshes its display every 1000 milliseconds (one second). This creates smooth, real-time updates without requiring any internet connection after the page loads. Everything runs locally in your browser.

Common Questions About Digital Clocks

Is this clock accurate?

The clock is as accurate as your device’s system time. Most computers and phones sync automatically with internet time servers (using NTP protocol), keeping them accurate to within a few milliseconds. If your device time is wrong, the clock will show that wrong time. You can fix this by enabling automatic time sync in your device settings.

Why does my time look different on other websites?

Different sites might show different times for a few reasons. Some use server time instead of your local time, some don’t account for daylight saving properly, and some cache old time data. This clock always uses your device’s current time, so it stays in sync with your system clock and other apps on your device.

Does this work offline?

Yes, completely. Once the page loads, the clock runs entirely in your browser using JavaScript. No internet connection needed. The only thing you can’t do offline is switch to different time zones for the first time, since those require the timezone database to load. But your selected timezone keeps working even if you lose connection.

What’s the difference between 12-hour and 24-hour time?

12-hour format splits the day into two periods (AM and PM) and counts from 1 to 12 twice per day. 24-hour format counts straight from 0 to 23, so there’s no ambiguity. In 24-hour time, 13:00 is 1:00 PM, 18:00 is 6:00 PM, and 00:00 is midnight. Most of the world uses 24-hour time by default, but the US primarily uses 12-hour format.

How do I use this for international meetings?

Select the time zone where your meeting is happening or where the other person is located. The clock instantly shows what time it is there right now. This helps you avoid the mental math of figuring out time differences. For example, if you’re in New York and need to call someone in Sydney, switch to Sydney time to see if they’re awake or if it’s the middle of their night.

Does this handle daylight saving time automatically?

Yes. The browser’s built-in timezone database knows when each region observes daylight saving time and adjusts automatically. When you select “London,” it shows GMT in winter and BST in summer. Same for all other regions. You don’t need to manually account for these changes.

Can I use this as a screensaver or always-on display?

Sort of. Use fullscreen mode and the clock fills your screen, which works great for presentations or if you want a big visible clock. But most browsers will eventually put inactive tabs to sleep to save resources, which might pause the clock. For a true always-on clock, keep the tab active and visible, or consider preventing your screen from sleeping in your device settings.

Time Format Reference

Time Zone Quick Reference

Time zones are based on the IANA Time Zone Database. UTC offsets may vary during daylight saving time transitions. This clock automatically adjusts for DST when applicable.