How accurate are the clocks?

The clocks update every second using your device's system clock and the browser's Intl.DateTimeFormat API. The accuracy depends on your system clock, which is typically synchronized to within a few seconds of UTC via NTP.

Will my timezone selections be saved?

Yes. Your selected timezones are saved in your browser's localStorage so they persist between visits. They are stored only on your device and never sent to any server.

What is the difference between GMT and UTC?

GMT (Greenwich Mean Time) and UTC (Coordinated Universal Time) are practically the same for everyday purposes. UTC is the modern scientific standard; GMT is a timezone that happens to equal UTC in winter. London observes BST (UTC+1) in summer.

Why does Tokyo always show the same UTC offset?

Japan does not observe Daylight Saving Time, so Tokyo is always UTC+9. Countries like Japan, China, India, and most of Africa have a constant offset year-round.

DST (Daylight Saving Time) is the practice of shifting clocks forward by one hour in spring to extend evening daylight. The "DST" badge appears when a city is currently observing DST, meaning its UTC offset is temporarily different from the standard.

World Clock - Live Time in Every Timezone

How to use the world clock

The world clock displays live, continuously updating times for any city or timezone. By default it shows New York, London, Tokyo, and Sydney, four key reference points that cover the Americas, Europe, East Asia, and Oceania.

To add more cities, type in the search box and select from the list. Your selection is saved in your browser and will be there the next time you visit.

Reading the clock cards

Time: Displays in 12-hour format (AM/PM). The large digits update every second.
Card color: Blue/light for daytime (8 AM–6 PM), amber for sunrise and sunset (6–8 AM, 6–8 PM), and dark for nighttime.
UTC offset: Shows the timezone's current offset from UTC, e.g. UTC+9 or UTC-5.
DST badge: Appears when that city is currently observing Daylight Saving Time, meaning its offset has shifted by +1 hour from standard.

Key world city times

City	Timezone	UTC offset (standard)	Observes DST?
New York	America/New_York	UTC−5 (EST)	Yes -> UTC−4 in summer
Chicago	America/Chicago	UTC−6 (CST)	Yes -> UTC−5 in summer
Denver	America/Denver	UTC−7 (MST)	Yes -> UTC−6 in summer
Los Angeles	America/Los_Angeles	UTC−8 (PST)	Yes -> UTC−7 in summer
São Paulo	America/Sao_Paulo	UTC−3	No (as of 2019)
London	Europe/London	UTC+0 (GMT)	Yes -> UTC+1 (BST) in summer
Paris / Berlin	Europe/Paris	UTC+1 (CET)	Yes -> UTC+2 (CEST) in summer
Moscow	Europe/Moscow	UTC+3	No (since 2014)
Dubai	Asia/Dubai	UTC+4	No
Mumbai / Delhi	Asia/Kolkata	UTC+5:30	No
Bangkok	Asia/Bangkok	UTC+7	No
Singapore / Beijing	Asia/Singapore	UTC+8	No
Tokyo	Asia/Tokyo	UTC+9	No
Seoul	Asia/Seoul	UTC+9	No
Sydney	Australia/Sydney	UTC+10 (AEST)	Yes -> UTC+11 (AEDT) in austral summer
Auckland	Pacific/Auckland	UTC+12 (NZST)	Yes -> UTC+13 (NZDT) in austral summer

Why do clocks differ from what I expect?

The most common cause is Daylight Saving Time. During DST, clocks are advanced by one hour, so the UTC offset temporarily changes. The DST badge on the card shows when this is in effect.

Another cause: some timezones observe non-integer offsets like UTC+5:30 (India) or UTC+9:30 (Adelaide, Australia). These are correctly handled by the IANA timezone database used in this tool.

Business hours overlap

When scheduling cross-timezone meetings, knowing the working-hours overlap is critical:

City pair	Approximate overlap (standard time)
New York – London	5 hours (9am–12pm ET = 2pm–5pm GMT)
New York – Paris	4 hours
New York – Tokyo	Essentially none (business hours are opposite)
London – Singapore	1–2 hours (end of London day = start of Singapore afternoon)
Los Angeles – London	0–1 hour (only at the London end of the day)

Daylight Saving Time schedule

United States: clocks spring forward the 2nd Sunday in March; fall back the 1st Sunday in November.
European Union: clocks change the last Sunday in March and last Sunday in October.
Countries without DST: China, Japan, India, most of Africa, and Iceland observe no DST. Their UTC offsets are constant year-round.
During the 2–3 week gap between US and EU transitions, offsets between them temporarily differ by 1 hour from their usual values.

IANA timezone database note

This tool uses the IANA timezone database (also called the Olson database), which is the definitive source for time zone rules used by operating systems, browsers, and most programming languages. Timezones are identified by region/city names (e.g., America/New_York, Europe/London) rather than offset strings like UTC-5. This is important because the correct offset at any given moment depends on DST status, which the IANA name handles automatically.