Flight Time & Distance Calculator
Estimate flight duration and great-circle distance between any two major cities. Useful for trip planning, layover decisions, and jet lag preparation.
How flight time is calculated
Flight duration depends on three main factors: the great-circle distance between airports (the shortest path along the curve of the Earth), the aircraft cruise speed (typically 850 to 950 km/h for commercial jets), and prevailing winds. The jet stream blowing west to east means flights from London to New York are about an hour longer than the return, and flights between Asia and North America vary by 1 to 2 hours depending on direction. We assume an average ground speed of 900 km/h plus 30 minutes for taxiing and approach, which is accurate for most non-stop commercial routes.
Longest non-stop commercial flights in the world
- Singapore to New York (Newark): 15,344 km, around 18 hours 45 minutes (Singapore Airlines)
- Auckland to New York: 14,134 km, around 17 hours 35 minutes (Air New Zealand, Qantas)
- Perth to London: 14,499 km, around 17 hours (Qantas)
- Dubai to Auckland: 14,200 km, around 17 hours (Emirates)
- Singapore to Los Angeles: 14,099 km, around 17 hours 50 minutes (Singapore Airlines)
Surviving long-haul flights
Flights over 8 hours need preparation. Stay hydrated (drink 250ml every two hours and avoid alcohol). Wear compression socks to reduce DVT risk. Walk the aisle every 2 hours. Set your watch to destination time at takeoff and start eating, sleeping, and waking on that schedule. Bring noise-cancelling headphones, an eye mask, and earplugs. Choose seats wisely: window for sleeping, aisle for movement, exit row for legroom.
Should you book a layover or non-stop?
Non-stop flights are faster, lower stress, and reduce the risk of missed connections. They are typically 20 to 50 percent more expensive than connecting itineraries. For trips over 12 hours of flying, a 2 to 3 hour layover at a great hub airport (Singapore, Doha, Dubai, Istanbul, Helsinki) provides a useful walking break. Avoid tight connections (under 90 minutes for international layovers) unless you are a confident traveller with carry-on only.
Frequently asked questions
Why is my flight time longer than this estimate?
Headwinds, indirect routing (planes cannot fly over certain countries), congested airspace, and weather diversions all add time. Flights heading east are typically faster than westbound flights of the same distance.
How is great-circle distance different from a straight line on a map?
On a flat map, the shortest path looks like a straight line, but the Earth is round. The great-circle is the actual shortest path on a sphere, which appears as a curved line on most map projections. This is why flights from New York to Tokyo cross over Alaska rather than going directly across the Pacific.
How early should I arrive at the airport?
For domestic flights, 90 minutes before departure is standard. For international flights, 2.5 to 3 hours is recommended. At very busy airports (Heathrow Terminal 5, JFK Terminal 4) during peak hours, allow 3 hours.