DocomintZeitzonenrechner
Konvertiere ein Datum und eine Uhrzeit von einer Zeitzone in eine andere, über 20 wichtige Städte.
What is a Zeitzonenrechner?
Converts a wall-clock date and time from one IANA time zone to another — correctly accounting for each zone's current daylight-saving offset at that specific date, rather than assuming a fixed year-round UTC offset, which is what makes most naive timezone math wrong by an hour during part of the year.
How to use the Zeitzonenrechner
- Enter a date and time, then choose the source and destination time zones
- Press Convert
- The converted date/time and the hour difference appear instantly, computed on your device
Formula
Converted Time = Source Time − Source UTC Offset + Target UTC Offset, using each zone's actual offset on that specific date
Offsets are looked up for the exact date/time entered, which automatically reflects whether either zone is observing daylight saving time on that date.
Example
2:30 PM on August 8, 2026 in New York (EDT, UTC−4 in August) converts to 3:30 AM the next day in Tokyo (UTC+9, no DST) — a 13-hour difference that would be different in winter, when New York shifts to EST (UTC−5).
Common mistakes
- Assuming a fixed, year-round UTC offset for a zone rather than one that shifts with daylight saving time across the year.
- Forgetting a small number of zones (India, Iran, parts of Australia) use 30- or 45-minute offsets, not whole hours.
- Converting a date right around a DST transition without checking which side of the change it actually falls on.
Frequently asked questions
Does this account for daylight saving time changes?
Yes — the conversion looks up each time zone's actual UTC offset at the specific date and time you entered, which automatically reflects whether that zone is in daylight saving time or standard time on that date, rather than assuming a fixed year-round offset.
Why isn't the time difference between zones always a round number of hours?
Most time zones do use whole-hour offsets from UTC, but a handful (India, Iran, parts of Australia) use 30- or 45-minute offsets — converting to or from one of those zones can produce a non-round difference like 9.5 or 5.5 hours.
Does this handle the date changing, not just the time?
Yes — a large enough time difference between zones can push the converted result into the previous or next calendar day, and the tool's output reflects that correctly rather than just showing a wrapped-around clock time.
Which cities use 30-minute offsets?
Among the zones this tool supports, Mumbai/Delhi (India, UTC+5:30) is the clearest example — a handful of other regions worldwide also use 30- or 45-minute offsets, which can produce a non-round hour difference when converting to or from them.
Is my numbers uploaded anywhere?
No — Zeitzonenrechner runs entirely in your browser using JavaScript/WebAssembly. Your numbers is never sent to a server.