World Clock — Multiple Cities

Multi-city world clock

This multi-city world clock shows the live time and date in cities around the globe, side by side. Add the places you care about and each appears with its UTC offset and how many hours it is ahead of or behind your own device. It is ideal for scheduling international calls, coordinating remote teams, and tracking markets or family abroad.

How it works

The clock reads your device’s current time once per second and converts it into each city’s local time using your browser’s built-in IANA time-zone database through the Intl API — the same data your operating system uses. Because each city carries its own daylight-saving rules, transitions are applied automatically, and offsets that aren’t whole hours (like India at UTC+5:30) display correctly. The difference versus your own zone is computed live, so it stays right even when a city shifts for daylight saving.

Example

If your device is in London (UTC+1 in summer) and you add Tokyo (UTC+9), the row shows Tokyo as +8 hours. When it is 09:00 for you, Tokyo reads 17:00 — handy for finding a meeting slot that suits both.

It is privacy-first — no location is shared and no clock data is fetched; everything runs locally.

Finding a meeting time that works across multiple time zones

The most common use for a world clock is scheduling — finding a window that falls within working hours for people in several locations. A practical approach:

1. Add all the cities where participants are located.
2. Read the “vs your time” column for each city to build a mental picture of the offset pattern.
3. Look for a band where most cities fall between 09:00 and 18:00 local time. With enough participants spread across zones, a perfect overlap rarely exists, so the goal is to minimize the inconvenience rather than eliminate it.

For teams spanning London and New York, the 14:00–17:00 London window (09:00–12:00 New York EST in winter) is the classic daily overlap. Add Singapore (UTC+8) and the overlap vanishes almost entirely — a morning London call is midnight in Singapore, and an afternoon Singapore call is early morning in New York. In those cases, rotating the inconvenience (alternating early and late calls) is more equitable than always asking the same location to accommodate.

UTC offsets and daylight saving — why the difference changes seasonally

UTC itself never changes — it is a fixed reference point. What changes is how many hours ahead of or behind UTC each country sits, because most countries observe daylight saving time (DST), shifting their clocks forward in spring and back in autumn. The trouble for international teams is that the shift dates differ by country: the United States typically changes clocks a few weeks before or after the United Kingdom, and some countries do not observe DST at all (China, India, Japan, and most of equatorial Africa stay on a fixed offset year-round).

This means the gap between London and New York is 5 hours for most of the year but 4 hours during the brief overlap when one has already changed and the other hasn’t. The browser’s IANA database handles all of this automatically — each city’s DST rules are encoded and applied correctly, so the offsets displayed here always reflect the actual current difference rather than a nominal annual average.

Non-whole-hour time zones

Several countries use offsets that are not on a whole hour:

• India (IST) = UTC+5:30
• Nepal = UTC+5:45
• Iran = UTC+3:30 (and UTC+4:30 during DST)
• Australia’s central zone = UTC+9:30 (and UTC+10:30 during DST)
• Myanmar = UTC+6:30
• Marquesas Islands = UTC−9:30

These display correctly in the tool as half-hour or quarter-hour offsets. When calculating the difference between two such zones and your own, the result will include .5 or .75 hours — for example, the difference between UTC+5:30 (India) and UTC+1:00 (UK summer) is 4.5 hours. The “vs your time” column in the clock shows these fractional differences accurately.