World clock

How to use the world clock

What it calculates and when to use it

A live world clock that shows the current time, date and UTC offset in cities around the world, and how far ahead or behind each one is compared with you. Add the cities you need and the list is remembered in your browser. Daylight saving is handled automatically.

How to use it, step by step

1. Your local time shows at the top.
2. Type a city name in “Add a city” and press Add.
3. Pick 12-hour or 24-hour style, or leave it automatic.
4. Remove a city with the × button, or reset to the default list.

What each input means

• Add a city – A city from the list, or a time zone name such as Asia/Karachi.
• Clock style – Automatic follows your device, or choose 12-hour or 24-hour.

How to read the results

• Local time – Your time and date, updated every second.
• City clocks – For each city: the time, date, UTC offset and difference from you.

The formula

Each time is the current instant shown in that city’s time zone. The difference from you is the offset of that zone minus your offset, from your browser’s time zone data, which includes daylight saving rules.

A worked example

When it is 3:00 PM in London in October, it is 10:00 AM in New York, 7:30 PM in Delhi and 11:00 PM in Tokyo.

Assumptions and limits

• Times come from your device’s clock, so they are only as accurate as it is.
• Cities share a time zone, so one entry represents the whole zone.
• The list is stored only in this browser.

Common mistakes

• Forgetting that daylight saving starts and ends on different dates in different countries, so differences change during the year.
• Assuming half-hour zones such as India do not exist.
• Typing a country instead of a city.

Frequently asked questions

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