How to use this tool
Choose the source time zone, enter its local date and time, then choose the destination. The converter uses bundled IANA time zone rules for that date, rather than a fixed hour difference. Dates from 1900 through 2100 are supported. A time skipped when clocks move forward is rejected. If clocks move backward, choose the earlier or later occurrence of the repeated time. The result states the source UTC offset so you can verify the intended occurrence. Future government rule changes require a dataset update.
Try these values
On January 15, 2026, 09:00 in New York is 14:00 in London and 19:00 in Karachi. On March 15, New York has changed to daylight saving time while London has not, so the New York–London difference is four hours.
Put the date in first
It is easy to remember a time difference and use it for the wrong week. Put the date in before you compare the clocks, especially in March, October and November. The United States and Europe do not change their clocks on the same Sunday, and places such as India and Pakistan do not change them at all. A recurring meeting can therefore move on somebody’s local calendar even if the organizer keeps the same start time.
Make the invitation unambiguous
Share the destination date as well as the time. For a late-night call, one person may already be on the following day. If a local time happens twice during an autumn clock change, the earlier/later setting chooses the occurrence and the UTC result identifies it. For an important appointment, put that UTC instant or the explicit offset in your notes rather than relying on an abbreviation such as CST.
Common questions
Does the date matter?
Yes. Countries change clocks on different dates, and some do not change them at all. Always enter the actual date of your call.
What happens at midnight?
The result includes the full destination date. A conversion can move to the previous or next calendar day.
Which time zones are supported?
The list contains named IANA zones and aliases in the bundled dataset, including zones with half-hour and quarter-hour offsets. The dataset version is shown with the controls and result.
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