World Clock
Free world clock showing live time in multiple cities. Add any timezone, toggle 12h/24h format, and see day/night at a glance.
This world clock shows the current time in multiple cities simultaneously, updating every second. Each city appears as a card with the local time, date, UTC offset, and a day/night indicator. The clock uses the IANA timezone database built into your browser via the Intl.DateTimeFormat API, so daylight saving rules update automatically. Add or remove cities from a list of over 50 worldwide timezones and switch between 12-hour and 24-hour formats.
About World Clock
How the Clock Gets the Right Time
The clock reads your device's system clock once per second and formats that instant into each selected timezone using the IANA tz database. The tz database (also called the Olson database) contains roughly 600 zone identifiers covering every inhabited region on Earth, with the full history of offset changes and DST rules going back decades. IANA ships a new release every few months when a government changes rules - the 2025b release added a new zone for Chile's Aysén Region after it stopped observing DST on 5 April 2025.
Worked example: if your device clock reads 14:30:00 UTC on 15 July, the Europe/London formatter returns 15:30 (BST, UTC+1), America/New_York returns 10:30 (EDT, UTC-4), and Asia/Tokyo returns 23:30 (JST, UTC+9). All three values come from the same underlying millisecond timestamp, so they stay in lock-step to the second.
Clock Card Details
| Element | What It Shows |
|---|---|
| City name | The location (e.g. "London", "New York") |
| Current time | Live local time updating every second |
| Date | The current date in that timezone (may differ from yours near midnight) |
| UTC offset | The timezone offset from UTC (e.g. UTC+9, UTC-5) |
| Day/night icon | Sun icon for daytime (6 AM - 6 PM), moon icon for nighttime |
| Card background | Warm amber for daytime, dark slate for nighttime |
Default Cities
The clock starts with six commonly referenced cities:
| City | Timezone | UTC Offset (Standard) | UTC Offset (DST) |
|---|---|---|---|
| London | Europe/London | UTC+0 | UTC+1 (BST) |
| New York | America/New_York | UTC-5 | UTC-4 (EDT) |
| Tokyo | Asia/Tokyo | UTC+9 | No DST |
| Sydney | Australia/Sydney | UTC+11 (AEDT) | UTC+10 (AEST) |
| Dubai | Asia/Dubai | UTC+4 | No DST |
| Los Angeles | America/Los_Angeles | UTC-8 | UTC-7 (PDT) |
You can remove any of these and add different cities from the full timezone list.
World Timezone Reference
| UTC Offset | Major Cities | Notable Details |
|---|---|---|
| UTC-8 to -5 | LA, Denver, Chicago, New York | US mainland spans 4 time zones |
| UTC+0 | London, Lisbon, Accra | Greenwich Mean Time baseline |
| UTC+1 to +2 | Paris, Berlin, Cairo, Johannesburg | Most of Europe and Africa |
| UTC+3 | Moscow, Istanbul, Riyadh | Russia uses 11 time zones total |
| UTC+5:30 | Mumbai, Delhi, Bangalore | India uses a single 30-minute offset zone |
| UTC+8 | Beijing, Singapore, Perth | China uses one timezone for the entire country |
| UTC+9 | Tokyo, Seoul | Japan does not observe DST |
| UTC+12 | Auckland, Fiji | First places to see each new day |
| UTC+13/+14 | Samoa, Kiribati | Some Pacific islands are the furthest ahead |
Daylight Saving Time
The clock uses the IANA timezone database built into modern browsers via the Intl API. This database includes all daylight saving time rules and transition dates. When a city switches between standard time and DST, the offset and displayed time update automatically. Key DST facts:
| Region | Spring Forward | Fall Back | DST Offset |
|---|---|---|---|
| United States | 2nd Sunday of March | 1st Sunday of November | +1 hour |
| United Kingdom / EU | Last Sunday of March | Last Sunday of October | +1 hour |
| Australia (most states) | 1st Sunday of October | 1st Sunday of April | +1 hour (reversed seasons) |
| Japan, China, India | N/A | N/A | No DST observed |
For 3-4 weeks each spring and autumn, the US and UK are on different DST schedules. The offset between New York and London during this period changes from the usual 5 hours to 4 or 6 hours. The clock handles this automatically.
Common Uses for a World Clock
| Use Case | What to Look For |
|---|---|
| Scheduling international calls | Check working hours overlap between cities |
| Remote team coordination | See who is in their workday vs evening vs sleeping |
| Stock market hours | NYSE opens 9:30 AM ET, London Stock Exchange at 8 AM GMT, Tokyo at 9 AM JST |
| Travel planning | Know the local time at your destination before you arrive |
| Family abroad | Quick check before calling to avoid waking someone up |
| Live event timing | Convert event start times to your local timezone |
Key DST Dates for 2026
The US and UK are on different DST schedules, so the offset between New York and London changes twice a year for a few weeks at a time. Specific 2026 transition dates from timeanddate.com:
| Region | Clocks Forward | Clocks Back |
|---|---|---|
| United States | Sun 8 Mar 2026, 02:00 local | Sun 1 Nov 2026, 02:00 local |
| United Kingdom / EU | Sun 29 Mar 2026, 01:00 UTC | Sun 25 Oct 2026, 01:00 UTC |
| Australia (NSW, VIC, SA, ACT, TAS) | Sun 4 Oct 2026, 02:00 local | Sun 5 Apr 2026, 03:00 local |
From 8 Mar to 29 Mar 2026, London is only 4 hours ahead of New York instead of the usual 5. From 25 Oct to 1 Nov 2026, the gap widens to 6 hours. The time zone converter handles these edge weeks automatically, which is especially useful when scheduling calls that land in the three-week gap.
Global Business Hours at a Glance
When the London trading floor opens at 08:00 GMT, it is 03:00 in New York, 16:00 in Hong Kong, and 19:00 in Sydney. A world clock is the quickest way to see who is awake before you schedule. Major financial market hours in local time:
| Exchange | City | Local Open | Local Close |
|---|---|---|---|
| NYSE / NASDAQ | New York | 09:30 | 16:00 ET |
| London Stock Exchange | London | 08:00 | 16:30 GMT/BST |
| Tokyo Stock Exchange | Tokyo | 09:00 | 15:00 JST (lunch 11:30-12:30) |
| Hong Kong Exchange | Hong Kong | 09:30 | 16:00 HKT (lunch 12:00-13:00) |
| Shanghai Stock Exchange | Shanghai | 09:30 | 15:00 CST (lunch 11:30-13:00) |
| Euronext Paris | Paris | 09:00 | 17:30 CET/CEST |
| ASX | Sydney | 10:00 | 16:00 AEST/AEDT |
| Bombay Stock Exchange | Mumbai | 09:15 | 15:30 IST |
London and New York overlap for about 3.5 hours each trading day (13:30-16:30 GMT) - this window is when most transatlantic deal flow happens. Tokyo and London do not overlap at all: the gap between Tokyo's 15:00 JST close (06:00 GMT) and London's 08:00 GMT open is the quietest window on the global FX clock.
Timezone Quirks Worth Knowing
Not every timezone is a neat whole-hour offset from UTC, and a few decisions by governments surprise people scheduling calls for the first time:
- India, Iran, Afghanistan, Nepal, Myanmar, parts of Australia use half-hour offsets. Nepal uses UTC+5:45, the only timezone offset by 45 minutes.
- China officially uses one timezone (UTC+8) for the entire country despite geographically spanning five. In Xinjiang, the sun rises close to 10:00 official time in winter.
- Russia spans 11 timezones, the most of any country. Russia abolished DST permanently in 2014.
- Arizona (except the Navajo Nation) and Hawaii do not observe DST, so their offset to the US east coast changes twice a year.
- Kiribati uses UTC+14, the furthest-ahead civil time on Earth. Samoa moved across the International Date Line in December 2011, skipping 30 December entirely.
- Iceland sits geographically in the UTC-1 zone but uses UTC+0 year-round with no DST.
12-Hour vs 24-Hour Format
The 24-hour format removes AM/PM ambiguity and is the default in continental Europe, most of Asia, and all military, aviation, and rail schedules worldwide. The 12-hour format with AM/PM remains dominant in everyday use in the US, UK, Canada, Australia, and the Philippines. ISO 8601, the international date-and-time standard, specifies 24-hour format. For international meeting invites, 24-hour notation avoids the classic "12:00 AM vs 12:00 PM" midnight confusion (midnight is 00:00, noon is 12:00). The toggle on this page applies to all city cards at once.
Common Mistakes When Scheduling Across Timezones
- Forgetting the DST gap weeks. An 08:00 London / 09:00 Paris meeting is usually 03:00 New York, but for three weeks in March and one week in October it shifts by an hour. Confirm the date, not just the offset.
- Using "EST" year-round. New York is EST in winter and EDT in summer. The correct neutral term is "ET" or "New York time". Same for PT, CT, MT.
- Assuming the whole of India or China runs on city-level zones. Both are single-zone countries, so Mumbai and Delhi always match, and Beijing and Shanghai always match.
- Trusting Outlook's auto-convert on recurring meetings. If you create a weekly 09:00 London meeting, some calendar clients fix the UTC time while others fix the local time. After a DST change, half your attendees will see the slot move and half will not. Always re-confirm after clock changes.
- Ignoring the date line. Auckland (UTC+13 in summer) is often a full calendar day ahead of Los Angeles (UTC-7). Book a "Monday 10am LA" call and Auckland hears it as Tuesday morning.
To convert a specific time from one timezone to another, the time zone converter lets you pick an exact time and see the equivalent in any zone. For scheduling meetings across zones, the meeting time planner shows availability overlap visually. For counting the days between two dates across zones, try the date difference calculator. The clock runs entirely in your browser with no external requests.
Sources
Frequently Asked Questions
How accurate is the world clock?
The clock uses your device's system time and the Intl.DateTimeFormat API to convert it to each timezone. It updates every second. As long as your device clock is correct, the times shown will be accurate, including daylight saving adjustments.
Can I add more cities?
Yes. Use the search box to find any city or timezone. The list includes over 50 major cities. Type a city name and click it to add a new clock card. You can add as many cities as you want.
What do the sun and moon icons mean?
The sun icon means it is daytime (between 6 AM and 8 PM local time) in that city. The moon icon means it is nighttime. The card background also changes to reflect day or night.
Can I switch between 12-hour and 24-hour time?
Yes. Click the "24h" or "12h" button at the top to switch between formats. The toggle applies to all cities at once.
Does the clock account for daylight saving time?
Yes. The clock uses the IANA timezone database built into modern browsers, which includes all daylight saving time rules. Times automatically adjust when DST changes occur.
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