Airport Timezone Difference
Calculate the timezone difference between two airports. See local times, UTC offsets, and timezone names for both departure and arrival airports in real time.
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Output
Readme
What are time zones and why do airports use them?
A time zone is a region of the globe that observes a uniform local time. Internationally, time zones are expressed as offsets from Coordinated Universal Time (UTC) — for example, New York is UTC−5 in winter and UTC−4 in summer (during Daylight Saving Time). The world is divided into roughly 40 standard offset zones, though many countries also use half-hour or quarter-hour offsets.
Airports follow the civil time zone of the city they serve. IATA-coded airports each carry an IANA timezone identifier (such as America/New_York or Asia/Tokyo) that is kept accurate through Daylight Saving Time transitions. Knowing the timezone of both your departure and arrival airport is essential for scheduling connections, arranging pick-ups, and avoiding confusion when crossing multiple time zones on a single journey.
Tool description
Airport Timezone Difference lets you select any two IATA-coded airports and instantly see the timezone relationship between them. Choose a departure airport and an arrival airport from searchable dropdowns. The tool displays live local clocks for both airports, their UTC offsets, their full IANA timezone names, and the net hour difference between the two locations — all updated in real time every second.
Features
- Live local clocks for both airports, refreshed every second
- UTC offset displayed for each airport (e.g.
UTC+5:30) - Full IANA timezone identifier shown (e.g.
Asia/Kolkata) - Net time difference in hours between arrival and departure timezones
- Searchable dropdowns covering all large and medium IATA-coded airports worldwide
- Automatically reflects Daylight Saving Time — no manual adjustment needed
How it works
- Select the Departure airport and the Arrival airport from the searchable dropdowns.
- The tool fetches the IANA timezone name and UTC offset for each airport from the bundled
airport-data-jsdataset. - The browser's
Intl.DateTimeFormatAPI formats the current UTC time into the local time for each timezone — this means DST transitions are handled automatically by the runtime. - The time difference is calculated as
arrival UTC offset − departure UTC offset, rounded to the nearest hour. - All clocks update once per second so the display stays accurate throughout your session.
Use cases
- Flight planning: Know exactly what time it will be at your destination when you land, so you can plan sleep, meals, and meetings accordingly.
- Remote team scheduling: Quickly check whether a proposed meeting time is reasonable for colleagues departing from or arriving at a different city.
- Layover planning: When connecting through an intermediate hub, understand how the local time at the stopover relates to your final destination.
Options explained
| Field | Description |
|---|---|
| Departure airport | The origin airport. Use the search box to find airports by name or IATA code. |
| Arrival airport | The destination airport. Same search interface as departure. |
| Local time | The current civil time at that airport, displayed as HH:MM:SS and updated every second. |
| UTC offset | The current offset from UTC for that airport, e.g. UTC+9 or UTC−5. Accounts for DST. |
| Timezone | The IANA timezone identifier, e.g. Europe/London or Pacific/Auckland. |
| Time difference | Arrival offset minus departure offset, in whole hours. A positive value means the arrival city is ahead; negative means it is behind. |
Limitations
- Only large and medium airports with valid IATA codes are included; small private airfields and heliports are not listed.
- The UTC offset stored in the airport dataset is a fixed value for that timezone's standard or current offset. For the most accurate DST handling the tool relies on the browser's built-in
IntlAPI using the IANA timezone name. - The time difference is expressed in whole hours. Destinations with half-hour or quarter-hour offsets (e.g. India UTC+5:30, Nepal UTC+5:45) will show the correct offset labels but the difference field rounds to the nearest hour.
FAQ
Why does the time difference change at certain times of year? Daylight Saving Time does not start and end on the same date in every country. If one country has already switched clocks and the other has not, the offset between them temporarily shifts by one hour. The tool reflects the current real-world offsets via the browser's timezone database.
What does a negative time difference mean? A negative value means the arrival city is behind the departure city. For example, flying from Tokyo (UTC+9) to London (UTC+1) gives a difference of −8 h.
Why does my airport not appear in the list? The dropdown includes large and medium airports with a valid IATA code. Very small regional airports, military bases, and seaplane bases are not included.
Is the UTC offset the same as the timezone? Not exactly. Two airports can share the same current UTC offset but belong to different timezones that diverge at DST transitions. The IANA timezone name (shown in the Timezone field) is the authoritative identifier; the UTC offset is the current numeric shorthand derived from it.