How to use the world clock
- Choose a base city and the current time of every city and its time difference from the base city are shown.
- Turn on Set time manually and enter a date and time to see what time that moment in the base city is in the other cities.
- The time updates automatically every second.
How the world clock works
World time is based on the standard time set for each region. This tool uses the international time zone data (IANA time zones) built into your browser, so cities with daylight saving time are calculated correctly for the date. For example, Seoul is 9 hours ahead of UTC with no daylight saving time, while New York is 5 hours behind UTC in winter and 4 hours behind during daylight saving time. The time difference between the same two cities can therefore change by an hour with the seasons. The difference is shown relative to the base city, and cities on a different date show the date and weekday too, so a one-day gap is easy to spot.
Tips
- When scheduling an international video call, use the manual time setting to check the other city's time first.
- Use it to check the opening hours of overseas stock or crypto markets.
- Check the time difference with your destination before a trip to plan your schedule more easily.
- It is also handy for choosing a good time to phone friends abroad.
How to calculate a time difference
The time difference between two cities is the difference between how far each is from UTC. Seoul (UTC+9) and London (UTC+0 in winter) are 9 hours apart, or 8 hours during daylight saving time. When the gap is large the date can differ, so when setting a meeting time check the date and weekday as well as the hour. This tool calculates both values automatically and shows the date, which reduces mistakes from doing the math by hand.
Notes & limitations
Daylight saving rules can change from country to country, and this tool follows the time zone data in your browser. For important events, confirm the time with the other person once more. If your device clock is wrong, the current time shown will be wrong too.
FAQ
Does it include daylight saving time?
Yes. It uses your browser's time zone data and applies daylight saving time automatically for the date.
Can I add other cities?
Currently about 30 major cities are provided. Please tell us which city you need on the contact page.
The current time looks different from the real time.
This tool uses your device clock. Check that your device's date and time are set to update automatically.