Travel Time & Jet Lag Calculator
Find your exact local arrival time when flying across time zones. Enter your departure time, flight duration, and the UTC offset difference to instantly see what time you'll land at your destination.
About this calculator
When you fly across time zones, your local arrival time isn't simply departure time plus flight duration. You must also add (or subtract) the UTC offset difference between your origin and destination. The formula is: arrivalTime = (departureHour + departureMinute/60 + flightHours + flightMinutes/60 + timezoneDiff) mod 24. The result is expressed in decimal hours on a 24-hour clock. For example, a positive timezoneDiff means the destination is ahead of your departure city. The modulo 24 operation handles cases where the total exceeds midnight, correctly rolling the time over into the next day. Understanding this calculation helps travelers plan ground transportation, hotel check-ins, and meetings upon arrival.
How to use
Suppose you depart New York (UTC−5) at 22:30 on a 7 h 45 min flight to London (UTC+0). The timezone difference is +5 hours. Enter departureHour = 22, departureMinute = 30, flightHours = 7, flightMinutes = 45, timezoneDiff = 5. Calculation: (22 + 30/60 + 7 + 45/60 + 5) mod 24 = (22 + 0.5 + 7 + 0.75 + 5) mod 24 = 35.25 mod 24 = 11.25, which equals 11:15 AM London time. You land at 11:15 AM local time the following morning.
Frequently asked questions
How do I calculate arrival time when crossing time zones on a flight?
Add your departure time (in decimal hours), the total flight duration (in decimal hours), and the UTC offset difference between origin and destination. Then apply modulo 24 to handle midnight crossings. For example, flying east generally adds hours to your clock, while flying west subtracts them. This calculator automates that arithmetic so you don't have to convert manually.
What does a positive or negative time zone difference mean in this calculator?
A positive timezoneDiff means your destination is ahead of your departure city in UTC terms — common when flying eastward, e.g., from the US to Europe. A negative value means the destination is behind, typical when flying westward, such as from Europe to the Americas. Enter the net difference: if departing UTC−5 and arriving UTC+9, enter +14.
Why does my calculated arrival time show a decimal instead of hours and minutes?
The formula returns time in decimal hours for simplicity. To convert, take the decimal portion and multiply by 60 to get minutes. For instance, 11.25 hours means 11 hours and 0.25 × 60 = 15 minutes, so 11:15. Many implementations then format this as HH:MM for display. If you see 23.75, that is 23:45 (11:45 PM).