Time Difference Calculator
See the time difference between two cities or timezones.
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Offsets are calculated for the current moment, so daylight saving time is accounted for automatically. The time is refreshed every 30 seconds. Note that the difference between two timezones can change by an hour several times a year as different regions switch between standard time and daylight saving time, and that not every country observes DST at all.
How to use the time difference calculator
The time difference calculator answers the question behind almost every international call, meeting, and flight booking: how far ahead or behind are these two places right now? It supports a broad set of city timezones and shows the current local time in each one alongside the offset from UTC.
The important detail is that this is not a fixed lookup table. The calculator computes each zone's offset for the current moment, which means it accounts for daylight saving time automatically. The offset for London is +0 in winter and +1 in summer, and for New York it is -5 in winter and -4 in summer, so the gap between them changes twice a year.
That seasonal change catches people out regularly. A business based in New York that schedules a recurring call with London at 9am Eastern will find that the London time shifts by an hour twice a year, and in the gap between the two US and UK changes the difference can be an hour wider than the nominal figure. The calculator always shows the current, correct answer rather than a standard-time approximation.
It is also worth remembering that not every country observes daylight saving time, and that the southern hemisphere flips the dates around: in January, Sydney is ahead of London by about nine hours, while in July it is ahead by about seven. The calculator handles this correctly because it evaluates the actual offset rather than assuming a rule.
A few countries have unusual arrangements worth knowing about. India and Nepal use half-hour and quarter-hour offsets from UTC. Some countries have changed their rules relatively recently, and the United Kingdom's permanent daylight saving experiment currently keeps it on summer time throughout the year. When precision matters for a scheduled event, the offsets shown here reflect the currently effective rules.
All calculations run locally in your browser using the IANA timezone database, so no request is made to an external time service.
Frequently asked questions
How is the time difference calculated?
Each timezone's offset from UTC is computed for the current moment using the IANA timezone database, which already accounts for daylight saving time. The difference between the two offsets is the answer.
Does this account for daylight saving time?
Yes. Because the offsets are evaluated for the current date rather than read from a fixed table, the result automatically reflects whether each region is currently on standard time or summer time.
Why does the difference change during the year?
Because different regions change their clocks on different dates. The gap between two timezones can vary by an hour, and in the weeks between two countries' transitions it can be wider than either country's standard difference.
What is the difference between UTC and GMT?
In practice they are the same offset, zero. UTC is the modern, precise standard; GMT is the older name and is technically a location in the UK. The distinction matters in legal text but not in time-zone arithmetic.
How do I schedule a meeting across timezones?
Pick your own timezone first, then find a time that lands within working hours for everyone else. The current local times shown for both zones make it straightforward to spot an overlap, and it is worth checking the other side's daylight saving rules before you commit to a recurring slot.
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