World Clock
Check current time in cities worldwide
Asia
Europe
Antarctica
North America
South America
Oceania
Africa
What is World Clock?
A world clock shows the current local time in many cities and time zones at once. It helps with international calls, remote teams, travel planning, livestream scheduling, customer support, market openings, and any situation where the other person’s local day matters. World time is based on time zones, UTC offsets, and sometimes daylight saving rules, not only on longitude. The same country can contain multiple time zones, and a city’s offset can change seasonally or by government decision. This page helps you browse countries and cities, compare local time, and confirm the UTC offset visible in the data. For legal deadlines, flight times, office hours, and holiday-sensitive planning, still confirm against the official source for that city or organization.
How to Use
How to use
- The top of the page automatically displays your local system time and timezone
- Type a country or city name in the search box to filter timezones
- The list shows each city's current time, date, weekday, and offset from local
- Offset shows the difference from local time - positive means ahead, negative means behind
Scheduling Tips
- Check the date as well as the hour when comparing distant timezones; the target city may already be on the previous or next day.
- For meetings around daylight-saving transitions, confirm the final time in calendar software before sending invitations.
Use Cases
Technical Principle
Every clock on the page is derived from the user's system time plus the IANA Time Zone Database (also known as the Olson database, tz database, or zoneinfo). The IANA TZDB is maintained by Paul Eggert and a small team at ICANN, released roughly four times a year with versions like `2024b` or `2025a`; each release encodes the historical and projected DST rules, civil offsets, and abbreviations for over 350 named zones such as `America/New_York`, `Asia/Shanghai`, and `Pacific/Chatham`. Browsers ship a snapshot of this database, exposed through the `Intl.DateTimeFormat(locale, { timeZone: 'Asia/Tokyo' })` API and the `timeZone` option on `toLocaleString`. `Intl.supportedValuesOf('timeZone')` enumerates the supported list; in Chrome it currently returns around 420 entries. The core formatting call is `new Intl.DateTimeFormat('en-US', { timeZone: 'America/New_York', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false }).format(new Date())`, which resolves the current UTC instant against the target zone's DST rule and returns the wall-clock time. UTC offset is computed by formatting the same instant with `timeZoneName: 'shortOffset'` (producing `GMT-5`) or `'longOffset'` (`GMT-05:00`). Half-hour and quarter-hour zones exist and are not edge cases: India (Asia/Kolkata) is UTC+5:30, Iran UTC+3:30 (with DST until 2022), Newfoundland UTC-3:30, Nepal UTC+5:45, the Chatham Islands UTC+12:45, and Marquesas UTC-9:30. DST transition rules are not symmetric across regions. The US shifts on the second Sunday of March (+1h, 02:00 → 03:00) and the first Sunday of November (-1h, 02:00 → 01:00), while the EU shifts on the last Sunday of March and the last Sunday of October at 01:00 UTC simultaneously across all member states. The southern hemisphere is opposite: Australia's eastern states shift on the first Sunday of October and April. Some zones with the same abbreviation are different zones — `CST` simultaneously means China Standard Time (UTC+8, no DST), Central Standard Time (UTC-6, US/Canada), and Cuba Standard Time (UTC-5) — which is why the IANA zone name should always be the source of truth in stored data, never the three-letter abbreviation.
- IANA Time Zone Database (tz/Olson) is the authoritative source: ~350 named zones, ~4 releases per year (e.g. `2024b`), maintained at ICANN.
- Browser API: `Intl.DateTimeFormat(locale, { timeZone: 'Area/City' })`; enumerate zones with `Intl.supportedValuesOf('timeZone')`.
- Sub-hour offsets are real: India +5:30, Iran +3:30, Nepal +5:45, Chatham Islands +12:45, Newfoundland -3:30, Marquesas -9:30.
- DST asymmetry: US shifts 2nd Sun of March / 1st Sun of November at 02:00 local; EU shifts last Sun of March / October at 01:00 UTC simultaneously.
- Southern hemisphere is reversed: Australia/Sydney shifts 1st Sun of October (+1h) and 1st Sun of April (-1h).
- Abbreviations are ambiguous: `CST` means China Standard (UTC+8), US Central Standard (UTC-6), and Cuba Standard (UTC-5) — always store the IANA name.
- Date line crossing: when local time is 09:00 Mon in Beijing (UTC+8) it is 20:00 Sun in New York (UTC-5) and 13:00 Sun in Honolulu (UTC-10), spanning two calendar days.
Examples
Cross-timezone Meeting Scheduling
When scheduling video calls across timezones, check working hours in each location to find a suitable time slot for everyone. For example, 9:00 AM in Beijing = 1:00 AM in London = 8:00 PM in New York (previous day).International Flight Planning
When booking international flights, knowing the local time at your destination helps adjust your schedule and reduce jet lag.Global Team Collaboration
When collaborating with team members in different timezones, quickly check if they're within working hours to avoid disturbing colleagues during rest time.FAQ
Which time zones can I add?
Any IANA zone - more than 400 of them, covering every country and region. Search by city (Tokyo, New York, São Paulo) or zone identifier (Asia/Tokyo, America/New_York). Daylight saving and historical zone changes are handled by the browser's underlying tzdata.
Why is the time slightly off?
The clock relies on your OS time, which should sync via NTP. If your laptop has been offline for a long time or has a misconfigured time zone, the displayed values shift accordingly. Sync your system clock first if accuracy matters.
Are daylight saving transitions handled?
Yes. The browser's Intl/IANA tzdata knows DST rules per zone, including historical changes. Note that some countries change DST rules occasionally (e.g. Mexico abolished DST in 2022); make sure your browser is recent enough to have current data.
Can I see UTC and the local zone difference?
Yes. Each city card shows local time plus the offset from UTC (e.g. UTC+9 for Tokyo, UTC-5 for New York). DST shifts are reflected automatically - New York shows UTC-4 in summer, UTC-5 in winter.
Will it work for meeting scheduling?
It shows current time in each zone, which is the most common use case. For finding overlapping working hours, look at all the card columns at once. For 'what does 3 PM in NYC convert to in Tokyo' use a dedicated meeting planner - this is a clock, not a meeting planner.
Can I save my favorite cities?
Yes - most builds save your selection to localStorage, so the same browser shows the same list next visit. Cross-device sync needs an account, which a basic clock doesn't have.
Is anything uploaded?
No. The clock reads system time and IANA zone data from the browser. Nothing is logged or transmitted.