Flight Time Calculator

Pick a city pair (or enter a custom distance in km or miles) and the calculator divides distance by an average cruise speed of 850 km/h, then adds 30 minutes of overhead for taxi, take-off, climb, descent and landing. London to New York at 5,570 km comes out at roughly 6 hours 56 minutes block time. London to Tokyo at 9,570 km lands near 11 hours 45 minutes. Sydney from Heathrow at 17,000 km is around 20 hours 30 minutes total flight time, which is why it is almost always flown as two legs.

These are great-circle distances, the shortest path over a sphere, which is what airlines actually fly when winds and airspace permit. Real-world block times are usually 10-30 minutes longer eastbound (against the jet stream) and 10-30 minutes shorter westbound (with it). London to New York eastbound averages 7h 30m on schedule, westbound 6h 30m, so split the difference and the calculator's 6h 56m is a fair midpoint estimate. Use the [Time Zone Converter](/time-zone-converter) to figure out what time you actually land at the destination.

Three things move the number around: jet stream tailwinds and headwinds (up to 200 km/h difference at cruise altitude), routing detours around restricted airspace (Russia closed to most Western carriers since 2022 added 1-3 hours to many Asia routes), and ground hold for traffic congestion at hubs like Heathrow, JFK and Singapore. London to Singapore on the old polar route was 13h 20m; via the southern route over Turkey and India it is 13h 50m to 14h 30m on most carriers in 2026.

The estimate also does not include connection time, immigration queues, baggage claim or transfer to your final accommodation. Add 1-2 hours for short-haul connections, 2-3 hours for long-haul transfers (Dubai is fast, LAX immigration on a non-US passport can chew through 90 minutes alone), and 30-90 minutes for arrival processing. Door-to-door London to Sydney via Singapore typically runs 26-28 hours including layovers. If you are doing it for the first time, the [Jet Lag Calculator](/jet-lag-calculator) plans your light exposure and meal timing so the second day does not flatten you.

Short-haul European: London to Paris 1h 30m, London to Amsterdam 1h 25m, London to Rome 2h 50m, London to Madrid 2h 30m. Mid-haul: London to Dubai 7h, London to New York 7h-8h, New York to Los Angeles 6h 15m. Long-haul: London to Tokyo 11h 45m, Los Angeles to Tokyo 11h 30m, London to Bangkok 11h 40m. Ultra long-haul: London to Sydney 21h+ (always with a stop), Singapore to Newark 18h 45m (Singapore Airlines, the longest scheduled flight in the world).

Domestic distances surprise people. Toronto to Vancouver is 3,360 km - longer than London to Cairo. Sydney to Perth is 3,300 km, a 5-hour flight in a country most foreigners assume is small enough to drive across in a weekend. Honolulu from Los Angeles is 3,840 km and 5h 45m, why Hawaii feels much further than it looks on most maps. The calculator covers 30 named routes plus a custom distance field for anything else.

Two scenarios where this matters. First: scheduling onward connections. If you land at JFK at 6pm local from London (11pm UK time) and need to fly internal to Miami, build in at least 3 hours for immigration, baggage and the inter-terminal walk; book your Miami flight no earlier than 9pm local. Second: stopover decisions. London to Bangkok direct is 11h 40m on Thai or BA; via Doha or Dubai is 14-16h with a 90-minute layover, but typically £100-£300 cheaper. Worth it if you can sleep on a plane, painful if you cannot.

For families with small children, anything over 6 hours benefits from a stopover. Tokyo direct from Heathrow with a 2-year-old is rough; breaking it in Doha for a hotel night turns 11h 45m of pain into two manageable 6-hour legs. Pair the result with the [Travel Budget Calculator](/travel-budget-calculator) to factor stopover hotel costs into the total. Long-haul economy seats are 31-32 inches of pitch on most airlines now in 2026, down from 34 a decade ago, so anything past 8 hours starts feeling cramped if you are over six foot.