Time Zone Converter — convert times between cities

How it works

Every time zone is defined as an offset from UTC (Coordinated Universal Time). To convert a time from one zone to another you take the difference between their offsets — but that difference isn't fixed, because many places shift their clocks for daylight saving part of the year. New York is 5 hours behind London in winter and 4 hours behind in summer, and the two don't switch on the same day, so the gap even changes for a week or two each spring and autumn.

This converter uses the IANA time-zone database (through your device's built-in copy) to look up each zone's exact offset on the date you choose, so daylight saving is always handled correctly. It also tells you when the converted time lands on a different calendar day — 11:00 PM in Los Angeles is 4:00 PM the next day in Tokyo.

Worked example

3:00 PM in New York → London, on a winter date:

• New York is UTC−5 (Eastern Standard Time), London is UTC+0 (GMT)
• Difference = +5 hours → 3:00 PM + 5 = 8:00 PM, the same day

11:00 PM in Los Angeles → Tokyo:

• Los Angeles UTC−8, Tokyo UTC+9 → +17 hours
• 11:00 PM + 17 h = 4:00 PM the next day

Frequently asked questions

Why do I need to pick a date?

Because time-zone offsets change with **daylight saving**, and countries switch on different dates. The gap between two zones can differ by an hour depending on the date, so the converter needs to know which day you mean to be exact.

How is daylight saving handled?

Automatically. The converter reads each zone's offset for the exact date you enter from the IANA database, so both the source and target zones use the right standard or daylight-saving offset — no manual "+1 hour" needed.

What if the time I enter was skipped by daylight saving?

On the spring-forward day, clocks jump ahead an hour, so a time in the skipped hour — for example 2:30 AM in a zone whose clocks go 2:00 → 3:00 — never actually happens. The converter treats such a time as the moment just **after** the jump. On the autumn fall-back day a time can occur twice; the converter uses the **earlier** of the two.

Why is the result sometimes a different day?

Because zones far apart can be more than a full day's clock apart. When adding the offset pushes the time past midnight, the result falls on the previous or next calendar day — shown as the "day change" of −1, 0 or +1.

What does the time difference mean?

It's how many hours the target zone is **ahead (+)** or **behind (−)** the source zone at that moment. Tokyo at +9 and New York at −5 gives a +14-hour difference, for example.

Which time zones are included?

A curated list of major cities across every region. Each is a full IANA zone (like `America/New_York` or `Asia/Tokyo`), so its daylight-saving rules are applied correctly.

Does it work for past and future dates?

Yes, within the daylight-saving rules known to the database — historical dates use the rules that were in effect then, and future dates use the current rules (which can change if a country alters its DST policy).