Time Zone Difference Calculator

How to use

Time difference between two cities: pick any two of the 40 supported cities — New York, London, Paris, Tokyo, Seoul, Sydney, Singapore, Dubai, Los Angeles, Toronto, Honolulu and more — and you'll see both current local times ticking live, along with the exact difference. What time will it be there?: enter a date and time in the first city, and the calculator converts it to the second city's local date, weekday, and time. Use it to schedule international calls, catch a product launch or ticket sale announced in another time zone, check when a match kicks off in your local time, or figure out what time to phone family abroad. Everything runs in your browser — nothing you type is sent anywhere.

How time zone differences work

Every time zone is defined as an offset from Coordinated Universal Time (UTC). London sits at UTC+0 in winter and UTC+1 in summer; New York at UTC−5 and UTC−4; Tokyo at UTC+9 year-round. The difference between two cities is simply one offset minus the other: in July, Tokyo (UTC+9) minus New York (UTC−4) gives 13 hours. Most offsets are whole hours, but not all — India runs on UTC+5:30, so New York to Delhi is 9 hours 30 minutes in summer. A few zones even use 45-minute offsets, like Nepal. This calculator reads offsets from the IANA time zone database that ships with your browser, so you never have to look up which rule applies on a given date.

Daylight saving time — why the difference changes during the year

Daylight saving time (DST) moves clocks forward one hour in summer, and different regions switch on different dates:

• United States and Canada: second Sunday in March to the first Sunday in November (March 8 to November 1 in 2026)
• United Kingdom and the EU: last Sunday in March to the last Sunday in October (March 29 to October 25 in 2026)
• Southern hemisphere (Sydney, Melbourne, Auckland): reversed — roughly October to April, since their summer falls over the new year
• No DST at all: Japan, South Korea, China, India, Southeast Asia, and the UAE — and within the US, Hawaii and most of Arizona stay on standard time year-round

Because the switch dates differ, some city pairs have "mismatch windows" where the usual difference temporarily changes. New York and London are normally 5 hours apart, but for about three weeks in March (March 8–28 in 2026) and one week from late October (October 25–31 in 2026), the gap narrows to 4 hours — a classic cause of missed calls. If a date near a DST boundary matters, don't rely on a memorized number: enter the actual date in the converter above and let the database decide.

Quick reference — hours relative to New York

Verified against the IANA time zone database for mid-July and mid-January. Values can differ by an hour for a few weeks around DST switch dates.

Finding a meeting time that works for everyone

The goal is the overlap of both sides' business hours — and how much overlap exists depends entirely on the pair:

• New York ↔ London (5 hours): the golden window is 9 a.m.–1 p.m. Eastern, which is 2–6 p.m. in London. Mornings in New York are the whole game — by 1 p.m. Eastern, London is packing up.
• New York ↔ California (3 hours): 12–5 p.m. Eastern maps to 9 a.m.–2 p.m. Pacific. Avoid early Eastern meetings — 9 a.m. in New York is 6 a.m. in San Francisco.
• US ↔ East Asia (13–14 hours from the East Coast): office hours never overlap. The common compromises are early morning US / evening Asia (8 a.m. Eastern is 9 p.m. in Seoul and Tokyo in July) or evening US / next-day morning Asia (8 p.m. Eastern is 9 a.m. the next day in Seoul).
• London ↔ Singapore (7 hours in summer): 9–11 a.m. in London reaches 4–6 p.m. in Singapore — workable, but only just.

Two habits prevent most scheduling disasters. First, always state the time zone explicitly ("3 p.m. Eastern", not just "3 p.m.") and double-check whether a recurring meeting is pinned to one side's local time — when DST switches, the other side's clock time shifts by an hour, twice a year. Second, mind the date line: a Friday-evening call in California is already Saturday morning in Sydney, so "let's talk Friday" can silently mean two different days.

Frequently asked questions

What is the time difference between New York and London?

London is usually 5 hours ahead of New York. The gap briefly narrows to 4 hours when the two regions switch to daylight saving on different dates — about three weeks in March and one week from late October to early November. In 2026 those windows are March 8–28 and October 25–31.

How do I calculate the time difference between two cities?

Subtract one city's UTC offset from the other's. New York in summer is UTC−4 and Tokyo is UTC+9, so Tokyo is 9 − (−4) = 13 hours ahead. The tricky part is daylight saving, which changes offsets twice a year on dates that vary by country — the calculator above applies the correct offsets for any date automatically.

Does this calculator handle daylight saving time?

Yes. It uses the IANA time zone database built into your browser, so DST start and end dates are applied automatically for every city — including past and future dates you enter in the converter. And since everything runs locally, nothing you type is ever sent to a server.

What is the best time to schedule a meeting across time zones?

Aim for the overlap of both sides' working hours: mornings in New York for London, mornings in London for Asia, and early morning or evening US time for East Asia, where office hours never overlap. Enter your proposed time in the converter above to see exactly what the clock reads on the other side — including the weekday, which matters near the date line.