Time Zone Converter
Convert a date and time from one city to another. AlarmPick turns the source city's local clock time into one exact moment, then shows that same moment in the destination city.
Loading the current time in the source city.
How to convert time between cities
A time zone converter answers a planning question: when it is a chosen clock time in one city, what clock time is that in another city? You pick the source city, the date, and the time. You pick the destination city. Convert shows the destination's local date, weekday, time, and the UTC offset in effect for that moment. To compare what time it is right now in several cities, use the current time around the world. The time you type is a wall-clock time you choose, not automatically the current time on this device.
How to use it
- Search for the source city, country, or time zone name, such as America/New_York.
- Choose the source date and time. Those fields belong to the source city, not to the destination.
- Search for the destination city. It does not have its own date or time field.
- Press Convert. If daylight saving makes the source time invalid or ambiguous, the page says so before it shows a result.
Why time zone conversion is more than adding hours
A named time zone is a region with rules, not a permanent number of hours from UTC. New York uses America/New_York. London uses Europe/London. Seoul uses Asia/Seoul. The offset attached to that name can change when the region starts or ends daylight saving time. Adding a fixed number of hours to a clock time goes stale as soon as one side changes its offset. AlarmPick stores the city and its IANA time zone, resolves the source clock time to one instant, and formats that instant in the destination zone.
Daylight saving time and ambiguous local times
On the day a region moves clocks forward, a range of local times never occurs. A clock that jumps from 2:00 to 3:00 skips every time in between, so 2:30 cannot be converted until you pick a time that exists. On the day clocks move back, a range of local times occurs twice: once before the change and once after it. Those two moments have different UTC offsets. AlarmPick lists both and waits for you to choose. It does not guess. The destination side has no second choice, because one chosen instant has one local representation in the destination zone.
During a spring transition the skipped interval is not always one hour. Some regions move the clock by 30 minutes. The suggestion after a missing time is the next local time that exists, searched forward up to three hours. Applying it fills the source time. It does not change the time silently.
During a fall transition the repeated time is labeled as the first occurrence and the second occurrence, each with the UTC offset that distinguishes it. Choose the earlier offset when you mean the time before clocks fall back. Choose the later offset when you mean the time after clocks fall back.
UTC offsets and named time zones
New York is not always UTC−5. In winter, America/New_York is normally UTC−5. In summer it is normally UTC−4. London can be UTC+0 in winter and UTC+1 in summer. Seoul does not use daylight saving time, so Asia/Seoul stays at UTC+9. India and Nepal show that offsets are not always whole hours: Asia/Kolkata is UTC+5:30, and Asia/Kathmandu is UTC+5:45. The offset on the result is calculated for the converted instant. It is not a number stored on the city.
Planning across time zones
- Set a meeting by converting the time you will dial from the city where the other person will be.
- Check a flight or a train departure in the departure city's local time, then see what clock time that is where you will land or arrive.
- Compare a remote teammate's working hours with yours before you send a message that needs a reply the same day.
- Read an event listing published in one city and convert it before you add it to a calendar kept in another city.
What this page does not do
- AlarmPick does not read your location or your IP address. The starting cities depend only on whether you opened the English or Korean page.
- The starting date and time are the current instant shown as the source city's wall clock, taken after the page loads in this browser. They are not a clock frozen when the site was built.
- Supported years are 1900 through 2100. Browser time zone data is not a promise of perfect historical rules before modern time zone standards.
- The converter does not save a history of the dates and times you convert, and it does not put them in the page address.
- This page does not create a city page, a city-pair page, or a link for every combination of cities.
Questions
What is a time zone converter?
A time zone converter takes a date and time in one city and shows the matching local date and time in another city.
How does AlarmPick convert time between cities?
It reads the source date and time as wall-clock time in the source city's IANA time zone, resolves that clock time to one instant, and formats the same instant in the destination city's time zone.
Does the converter account for daylight saving time?
Yes. Daylight saving follows the time zone data in your browser. The UTC offset on the result is the offset for the converted instant, not a fixed annual difference.
Why does a local time sometimes not exist?
During a spring daylight saving transition, clocks can jump forward and skip a range of local times. A skipped time cannot be converted until you choose a time that exists.
Why can the same local time occur twice?
During a fall daylight saving transition, clocks can move back and repeat a range of local times. AlarmPick shows both occurrences and their UTC offsets so you can choose the one you mean.
Is New York always UTC−5?
No. New York normally switches between UTC−5 and UTC−4 because of daylight saving time. The reliable name is America/New_York.
Does AlarmPick use my location?
No. AlarmPick does not read your location or your IP address. English starts from New York to London. Korean starts from Seoul to New York.
Can the converted date be different from the source date?
Yes. The destination can fall on the previous day, the same day, or the next day. The page compares the two civil dates of the same instant rather than dividing milliseconds by the length of a day.