Why does time-zone conversion depend on the date?
In many zones such as London, New York, Berlin and Sydney, the UTC offset can change during the year because of daylight saving time. A fixed “+3 / −5” difference can therefore be wrong for past or future dates.
This tool uses the browser’s IANA time-zone data to apply the regional rules in effect on the selected date.
DST gaps and repeated local times
When clocks move forward, some local times never occur. When clocks move back, a time such as 01:30 can refer to two different real instants. The calculator handles both cases explicitly instead of guessing.
Global location support
The search list includes hundreds of cities and IANA reference locations, and all IANA time zones supported by your browser can be selected. If a city is not listed, choose the correct IANA zone manually.
Frequently asked questions
Is the time difference between Istanbul and New York always the same?
No. Türkiye uses UTC+3 year-round while New York observes daylight saving time, so the difference changes during the year.
Are UTC and GMT the same?
For everyday clock conversions they usually represent the same zero offset; technically, UTC is an atomic time standard while GMT is a historical/time-zone term.
What happens if I enter a nonexistent DST time?
The calculator reports that the local time never occurs in that zone and stops the conversion.
What if my city is not in the list?
If you know your city’s IANA time zone, select it directly from the time-zone list.