How to use this calculator
Select your departure and arrival cities from the dropdown menus, set your departure date and time, and the calculator will instantly estimate your flight duration and arrival time in the destination's local time zone.
Use the popular route presets to quickly load common city pairs, or add a layover to see how a connecting flight affects your total travel time. The calculator uses the Haversine formula to compute great-circle distances and assumes an average cruising speed of 550 mph.
Understanding time zones and jet lag
When you cross time zones, your body's internal clock needs time to adjust. As a general rule, it takes about one day per time zone crossed to fully acclimate. Eastward travel tends to cause more jet lag than westward travel because it's harder for most people to advance their sleep schedule than to delay it.
To minimize jet lag, stay hydrated during the flight, avoid alcohol and caffeine near your planned sleep time, and try to get sunlight exposure at your destination during morning hours.
Frequently asked questions
How long is the flight from New York to London?
A direct flight from New York to London takes approximately 7 hours eastbound and about 8 hours westbound. The difference is due to the jet stream, a high-altitude wind current that typically flows west to east across the Atlantic.
How are flight times calculated?
Flight time estimates are calculated using the great-circle distance between two cities (the shortest path along Earth's surface) divided by average cruising speed (around 550 mph for commercial jets), plus approximately 30 minutes for takeoff, climb, descent, and landing. Actual times vary based on wind, routing, and aircraft type.
Do time zones affect when I arrive?
Yes, time zones significantly affect your local arrival time. When flying east you lose hours (clocks move forward), and when flying west you gain hours (clocks move back). For example, a 5-hour flight from New York to London with a +5 hour time zone change means you arrive 10 hours later in local London time.
How much layover time should I allow between connecting flights?
For domestic connections, allow at least 60-90 minutes. For international connections where you need to clear customs and immigration, allow at least 2-3 hours. If your connection involves changing terminals, add an extra 30-60 minutes.
Why do westbound flights take longer than eastbound flights?
Westbound flights often take longer because commercial aircraft fly against the jet stream, a band of strong winds that flows from west to east at high altitudes. This headwind slows the aircraft's ground speed. Eastbound flights benefit from a tailwind, which increases ground speed and shortens the flight.