Timezone Difference
Calculate the hour difference between any two time zones.
13h
Tokyo 13h ahead
New York
UTC-4:00
Tokyo
UTC+9:00
How It Works
- 1
Select two timezones
Choose a source and target timezone from the searchable dropdown. You can search by city name, country, or IANA zone identifier.
- 2
View the difference
The calculator displays the exact hour and minute offset between the two zones for today's date, including DST status for both. A timeline visualization shows the relationship clearly.
- 3
Check other dates
Change the date to see how the difference varies throughout the year due to DST transitions. The calculator highlights dates when the offset changes.
Understanding Time Zone Differences
The Timezone Difference calculator gives the hour and minute offset between two IANA timezones for a specific date. New York is often described as 5 hours behind London, but that is only true for part of the year. During the weeks when the US and UK change clocks on different dates, the gap is 4 hours. The calculator uses IANA rules to show which city is ahead, whether either zone is in DST, and when the next offset change occurs. It supports ordinary offsets as well as UTC+5:30, UTC+5:45, UTC+13, and other less common timezone pairs.
Frequently Asked Questions
Why does the time difference between two cities change during the year?
Most time difference changes are caused by Daylight Saving Time. If two cities observe DST on different dates โ or if one observes it and the other does not โ their offset shifts temporarily. For example, the US and EU switch clocks on different weekends, creating a brief period each spring and autumn when the usual difference changes by one hour.
Can two cities have a non-whole-hour difference?
Yes. Several timezones use half-hour or even quarter-hour offsets. For instance, the difference between London (UTC+0 or UTC+1) and Mumbai (UTC+5:30) is always 5 hours 30 minutes or 4 hours 30 minutes, depending on British Summer Time.
What is the largest possible time difference between two places?
The maximum difference is 26 hours, between UTC-12 (Baker Island) and UTC+14 (Line Islands, Kiribati). In practice, the most common large difference is about 17-18 hours, between US West Coast and East Asia or Oceania timezones.