How accurate is the time shown?

The clocks use your device clock and IANA time-zone rules for each city. Accuracy depends on your device time, which most operating systems keep close to real time with network sync. For a sanity check, use Exact Time; it is not a certified atomic-clock reference.

Does the world clock handle daylight saving time?

Yes. Each city is tied to an IANA zone such as America/New_York or Europe/London, so current offsets and daylight-saving transitions are applied automatically.

Can I save the cities I add?

Yes. Your selected cities stay in local browser storage on the same device and browser. They do not sync across devices.

How many time zones are there in the world?

It depends on what you count. There are 24 one-hour zones if you only count the round hourly offsets, but in practice the world uses 38 or so distinct UTC offsets at once because several regions use half-hour and quarter-hour offsets. India is UTC+05:30, Nepal is UTC+05:45, and parts of Australia use UTC+08:45. The IANA tz database, the standard reference, divides the world into more than 340 named zones because each region with its own DST history needs its own entry.

UTC stands for Coordinated Universal Time. It is the world's reference clock, kept by atomic clocks rather than the position of the sun, and it never shifts for daylight saving. Every local time is defined as UTC plus or minus an offset. A world clock works by taking one UTC instant and re-displaying it for each region's offset, which is why all the clocks stay in sync.

Why isn't a UTC offset enough to identify a time zone?

An offset like UTC-05:00 tells you the gap from UTC right now, but not the rules. New York is UTC-05:00 in winter and UTC-04:00 in summer because it observes daylight saving time. A fixed offset cannot encode that schedule. The IANA zone ID America/New_York does — it stores every past and future transition date, so software can compute the correct offset for any moment in history.

Why does the US have daylight saving time but Arizona does not?

The US Uniform Time Act lets states opt out of daylight saving time, and Arizona did so in 1968. The usual explanation is climate: an extra hour of evening sunlight in an already very hot summer would increase air-conditioning use. The Navajo Nation, which spans Arizona, New Mexico, and Utah, does observe DST so its tribal lands keep one consistent clock across state lines.

What is the difference between GMT and UTC?

GMT, Greenwich Mean Time, is a time zone — the local time at the Greenwich meridian. UTC is a time standard defined by atomic clocks. They almost always show the same wall-clock time, but UTC is the precise technical reference and GMT is the everyday name for the same offset in the UK and elsewhere. For scheduling and software, prefer UTC and a named IANA zone.

Why do some countries have time zones offset by 30 or 45 minutes?

Time zones are political and historical, not purely geographic. A country can set its clocks to whatever offset suits commerce and daily life. India chose a single UTC+05:30 zone to unify a wide country under one clock. Nepal uses UTC+05:45, and the Chatham Islands use UTC+12:45. These fractional offsets are exactly why a world clock cannot rely on whole-hour math.

Does the whole world change clocks for daylight saving on the same day?

No. The European Union shifts on the last Sundays of March and October, the US and Canada shift on the second Sunday of March and first Sunday of November, and the southern hemisphere shifts in the opposite season. Many countries — most of Asia, Africa, and the tropics — never change at all. For a few weeks each spring and autumn, the gap between two cities can be one hour different from usual.

What is the International Date Line?

The International Date Line is the roughly 180-degree meridian where the calendar date changes. Cross it going west and you skip a day forward; cross it going east and you repeat a day. It is why a world clock can show two cities on different calendar dates at the same instant — Honolulu can still be in yesterday while Sydney is already in tomorrow.

How does a world clock stay accurate?

A world clock reads one trusted current time, usually the visitor's device clock synchronized to internet time servers, then applies each region's IANA time-zone rules to display the corresponding local time. Because the rules come from the IANA tz database, the clock automatically reflects daylight-saving transitions and any government time-zone changes once the data is updated.

Why do time zones exist at all?

Before standardized zones, every town kept its own solar time, which made railway and telegraph schedules chaotic. Standard time zones were adopted in the late 19th century so that large regions could share one clock anchored to a common reference. Today that reference is UTC, and time zones are simply the agreed offsets from it.

World clock.

Current time around the world

Current time in major cities around the world. Add cities to build your personalized dashboard.

Answer first

Keep one live board for the cities and time windows you care about..

Start with the dashboard, then open deeper visual demos only when you need them. The page stays quick while still giving you a complete time-zone workspace.

Add cities quickly and keep them synced in your browser.
See working hours and daylight without opening another tool.
Jump to compare, markets, widgets, or meeting planning when the question gets deeper.

Compare city pairs

See overlap windows, DST gaps, and the easiest time to call.

Open compare

Watch market hours

Check open-now and next-open windows for major exchanges.

Open markets

Plan meetings

Use overlap data to choose the least painful meeting slot.

Open planner

Share a clock

Embed a city clock anywhere with reusable widgets.

Open widgets

Practical checks

Use the world clock when the exact city matters

City-based clocks are safer than guessing from abbreviations. EST, CST, and IST can mean different things in different contexts, while a city maps to a concrete IANA time zone and follows local daylight-saving rules for the selected date.

Before you call

Confirm whether New York, London, Tokyo, Dubai, Singapore, or Sydney is in working hours before sending a message that expects a quick reply.

Before you publish

Check launch times, webinar starts, match kickoffs, and livestream windows in the cities where your audience is likely to be watching.

Before you compare

Use the board for a fast answer, then move to city comparison or the meeting planner when DST, overlap, or fairness becomes the real question.

Methodology

How this page keeps time trustworthy

Timezone data

City and timezone calculations use IANA timezone identifiers where possible, so offsets follow real regional rules instead of fixed UTC shortcuts.

DST handling

Daylight-saving changes are date-aware. If a region changes policy, regenerated pages pick up the updated rule set from the app data pipeline.

Accuracy limits

Live clocks depend on the visitor's device clock. They are useful for scheduling, but they are not a certified atomic-clock reference.

Local storage

Saved cities, teams, and preferences stay in the browser on the same device unless you explicitly share or export them.

Data-backed checks

Timezone rules

IANA tzdb

IANA identifiers keep offsets date-aware instead of fixed to one UTC shortcut.

City records

GeoNames

GeoNames-derived records anchor city pages, search, and popular hub lists.

Freshness

Apr 30, 2026

Live values render on request; editorial/source notes carry the reviewed date.

Sources: IANA tzdb, GeoNames-derived city records, Nager.Date, OurAirports, exchange calendars, and curated event source links. Source notes

Reviewed: Apr 30, 2026

Live snapshots: Current times, daylight, market states, and countdown values are rendered at request time; review dates describe the underlying content, not a guarantee that authorities, exchanges, airlines, or event organizers will not change schedules.

Live dashboard

Your cities, in one glance

Add cities, keep them in browser storage, and compare day, night, and working hours without loading the heavier demos first.

Day / night

Where is it day?

Scrub through the day to see the terminator line sweep across the globe. The shaded region marks nighttime; the lit region marks daytime at the selected moment.

Interactive demo

Day and night line

Scrub the terminator line without paying the rendering cost until this section is visible.

Arrange

Arrange your own clocks

Drag tiles to reorder. Your preferred arrangement stays with you as you compare overlapping working hours across teams.

Interactive demo

Drag and reorder clocks

Load the draggable board only when you need the interaction. The core clock board stays fast first.

Interactive

Interactive demos

These demos load on demand so the page stays fast until you scroll here or choose to reveal them.

Interactive demo

Interactive globe

See daylight sweep across the planet, while loading the 3D demo only when you want it.

Popular cities

Jump to a city

Start with major hubs that commonly appear in travel, remote work, finance, support coverage, and media scheduling. Each link opens the city page for live time, timezone context, and related comparisons.

New York London Tokyo Dubai Singapore Sydney Los Angeles Paris Berlin Mumbai Shanghai São Paulo

Browse

Browse by region

Americas Europe Asia Africa Oceania

FAQ

Frequently asked questions

How accurate is the time shown?: The clocks use your device clock and IANA time-zone rules for each city. Accuracy depends on your device time, which most operating systems keep close to real time with network sync. For a sanity check, use Exact Time; it is not a certified atomic-clock reference.
Does the world clock handle daylight saving time?: Yes. Each city is tied to an IANA zone such as America/New_York or Europe/London, so current offsets and daylight-saving transitions are applied automatically.
Can I save the cities I add?: Yes. Your selected cities stay in local browser storage on the same device and browser. They do not sync across devices.

How world clocks work

The mechanics behind every clock on this page

A world clock looks simple — a grid of cities, each ticking — but it rests on one idea: a single universal time, re-displayed for every region's rules. These notes explain that idea so the live dashboard is more than a number.

UTC is the single reference clock

Every clock on this page is the same UTC instant displayed differently. UTC, Coordinated Universal Time, is maintained by atomic clocks and never shifts for daylight saving. A world clock takes one UTC moment and re-renders it for each region using that region's offset, which is why all the city clocks stay perfectly in step with each other.

IANA zones, not bare offsets

A bare offset like UTC-05:00 is only true for an instant. The IANA tz database instead names each region — America/New_York, Asia/Tokyo — and stores its full history of offset and daylight-saving changes. That named zone is the canonical key behind every clock here, so the right offset is computed for the exact moment shown.

Why offsets alone break: daylight saving

Roughly a third of the world's population observes daylight saving time, and the switch dates differ by region. New York moves an hour in March; the EU moves a week or two later; the southern hemisphere moves in the opposite season. A clock that hard-coded a fixed offset would silently drift wrong for several weeks twice a year. The IANA rules encode every transition so the clock self- corrects.

38-plus offsets, not 24

The familiar "24 time zones" only counts whole-hour offsets. In practice the world uses around 38 distinct UTC offsets at once, because several regions use half-hour and quarter-hour offsets — India at UTC+05:30, Nepal at UTC+05:45, the Chatham Islands at UTC+12:45. The full range runs from UTC-12:00 to UTC+14:00, a 26-hour spread, which is why two cities can sit on different calendar dates.

The date line and the 26-hour spread

Because offsets span UTC-12 to UTC+14, the globe is never on a single calendar date. Cross the International Date Line going west and the date jumps forward a day. A world clock surfaces this directly: at one instant Honolulu can still read "yesterday" while Sydney already reads "tomorrow."

From a clock to a decision

The live dashboard answers "what time is it there right now." When the question becomes "what time should we meet," move to the converter or meeting planner; when it becomes "is their market open," use the markets pages. The clock is the entry point into those scheduling workflows.

Offsets are political and historical, not purely geographic. The IANA time-zone database is the canonical record of every region's offset and daylight-saving rules, and it is what keeps these clocks correct through every transition.

Offset reference

Major business cities and their UTC offsets

Standard offsets and daylight-saving behavior for the world's busiest commercial hubs, ordered west to east. Standard offset is the non-DST (winter) value; the DST column shows the summer offset where the region shifts. Open any city for its live clock.

City	IANA zone	Standard offset	DST offset	Daylight saving
Los Angeles	America/Los_Angeles	UTC-08:00	UTC-07:00	Observes US DST (Mar-Nov)
Chicago	America/Chicago	UTC-06:00	UTC-05:00	Observes US DST (Mar-Nov)
New York	America/New_York	UTC-05:00	UTC-04:00	Observes US DST (Mar-Nov)
São Paulo	America/Sao_Paulo	UTC-03:00	—	No DST since 2019
London	Europe/London	UTC+00:00	UTC+01:00	Observes EU-style DST (Mar-Oct)
Paris	Europe/Paris	UTC+01:00	UTC+02:00	Observes EU DST (Mar-Oct)
Berlin	Europe/Berlin	UTC+01:00	UTC+02:00	Observes EU DST (Mar-Oct)
Dubai	Asia/Dubai	UTC+04:00	—	No DST
Mumbai	Asia/Kolkata	UTC+05:30	—	No DST (half-hour offset)
Singapore	Asia/Singapore	UTC+08:00	—	No DST
Hong Kong	Asia/Hong_Kong	UTC+08:00	—	No DST since 1979
Shanghai	Asia/Shanghai	UTC+08:00	—	No DST (single nationwide zone)
Tokyo	Asia/Tokyo	UTC+09:00	—	No DST
Sydney	Australia/Sydney	UTC+10:00	UTC+11:00	Observes DST (Oct-Apr, southern summer)

Offsets and DST rules are from the IANA tz database. Where a region observes daylight saving, its clock differs from the standard offset for part of the year — always confirm against the live city clock for the current value.

Reference

Common time-zone questions

How many time zones are there in the world?: It depends on what you count. There are 24 one-hour zones if you only count the round hourly offsets, but in practice the world uses 38 or so distinct UTC offsets at once because several regions use half-hour and quarter-hour offsets. India is UTC+05:30, Nepal is UTC+05:45, and parts of Australia use UTC+08:45. The IANA tz database, the standard reference, divides the world into more than 340 named zones because each region with its own DST history needs its own entry.
What is UTC?: UTC stands for Coordinated Universal Time. It is the world's reference clock, kept by atomic clocks rather than the position of the sun, and it never shifts for daylight saving. Every local time is defined as UTC plus or minus an offset. A world clock works by taking one UTC instant and re-displaying it for each region's offset, which is why all the clocks stay in sync.
Why isn't a UTC offset enough to identify a time zone?: An offset like UTC-05:00 tells you the gap from UTC right now, but not the rules. New York is UTC-05:00 in winter and UTC-04:00 in summer because it observes daylight saving time. A fixed offset cannot encode that schedule. The IANA zone ID America/New_York does — it stores every past and future transition date, so software can compute the correct offset for any moment in history.
Why does the US have daylight saving time but Arizona does not?: The US Uniform Time Act lets states opt out of daylight saving time, and Arizona did so in 1968. The usual explanation is climate: an extra hour of evening sunlight in an already very hot summer would increase air-conditioning use. The Navajo Nation, which spans Arizona, New Mexico, and Utah, does observe DST so its tribal lands keep one consistent clock across state lines.
What is the difference between GMT and UTC?: GMT, Greenwich Mean Time, is a time zone — the local time at the Greenwich meridian. UTC is a time standard defined by atomic clocks. They almost always show the same wall-clock time, but UTC is the precise technical reference and GMT is the everyday name for the same offset in the UK and elsewhere. For scheduling and software, prefer UTC and a named IANA zone.
Why do some countries have time zones offset by 30 or 45 minutes?: Time zones are political and historical, not purely geographic. A country can set its clocks to whatever offset suits commerce and daily life. India chose a single UTC+05:30 zone to unify a wide country under one clock. Nepal uses UTC+05:45, and the Chatham Islands use UTC+12:45. These fractional offsets are exactly why a world clock cannot rely on whole-hour math.
Does the whole world change clocks for daylight saving on the same day?: No. The European Union shifts on the last Sundays of March and October, the US and Canada shift on the second Sunday of March and first Sunday of November, and the southern hemisphere shifts in the opposite season. Many countries — most of Asia, Africa, and the tropics — never change at all. For a few weeks each spring and autumn, the gap between two cities can be one hour different from usual.
What is the International Date Line?: The International Date Line is the roughly 180-degree meridian where the calendar date changes. Cross it going west and you skip a day forward; cross it going east and you repeat a day. It is why a world clock can show two cities on different calendar dates at the same instant — Honolulu can still be in yesterday while Sydney is already in tomorrow.
How does a world clock stay accurate?: A world clock reads one trusted current time, usually the visitor's device clock synchronized to internet time servers, then applies each region's IANA time-zone rules to display the corresponding local time. Because the rules come from the IANA tz database, the clock automatically reflects daylight-saving transitions and any government time-zone changes once the data is updated.
Why do time zones exist at all?: Before standardized zones, every town kept its own solar time, which made railway and telegraph schedules chaotic. Standard time zones were adopted in the late 19th century so that large regions could share one clock anchored to a common reference. Today that reference is UTC, and time zones are simply the agreed offsets from it.

World clock method

How we calculate this: Each clock takes one universal time instant and applies the target region's IANA time-zone rules to render local time. Offsets in the business-city table are the standard (non-DST) and daylight-saving values for each IANA zone; the live dashboard recomputes the exact current offset on the device so it always reflects the active rule.
Data sources: IANA Time Zone Database (tzdata) for all offset and daylight-saving rules; daylight-saving policy notes (for example the US Arizona exemption) follow the US Naval Observatory and the IANA tz data. City and zone routing comes from the in-app city and zone catalogs.
Update cadence: Offset and DST rules track the IANA tzdata release cycle, which publishes several updates a year; the values above are refreshed when the application is rebuilt against a new tzdata version. The live clocks tick every second from the visitor's synchronized device clock.

Reference data for world clocks

Reference fields include the universal-time reference, IANA tz database terminology, daylight-saving concepts, the UTC-12 to UTC+14 offset range, and the major business cities with their IANA zones and standard offsets.

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Current time around the world