Why does flight time differ by direction?

Jet stream — strong westerly winds at cruise altitude in the Northern Hemisphere. Eastbound transatlantic flights ride this tailwind: NYC-London is typically 6:30-7:00. Westbound flights face headwind: London-NYC is 7:30-8:00 (sometimes 8:30 with strong headwinds). Same airline, same aircraft, same route — direction matters dramatically. The difference is consistent (always favoring eastbound) but magnitude varies seasonally.

How fast do commercial jets fly?

Modern commercial jets cruise at 540-560 mph (870-900 km/h) true airspeed at typical cruise altitude (35,000-40,000 ft). Boeing 747, 777, A350: ~570 mph. Boeing 737, A320: ~540 mph. Regional jets (CRJ-700, Embraer 175): ~500-520 mph. Mach 0.78-0.85 typical (subsonic). Concorde was supersonic at Mach 2 but retired in 2003; Boom Supersonic working on Mach 1.7 jets for late 2020s commercial use.

What's great-circle distance?

Shortest distance between two points on a sphere. On Earth, looks curved on flat maps but straight on a globe. NYC to Tokyo great-circle goes OVER Alaska / Russia (looking at a globe makes this obvious). Latitude lines are NOT great circles (except the equator); they curve relative to actual shortest path. Modern jets fly close to great-circle routes; older flights followed political airspace and refueling stop constraints.

How accurate is the calculator?

Within ~10% of actual block time. Sources of variance: jet stream (±15-30%), routing detours, ATC delays, aircraft type variance. For booking decisions, use airline schedules. For general curiosity, calculator is fine. Caveat: calculator typically uses 540 mph cruise; some routes (high-altitude over polar regions) actually fly slightly faster due to stronger stratospheric winds.

Why are scheduled times longer?

Airlines pad scheduled times by 15-30 min beyond actual cruise + overhead time. Reasons: ATC delays at busy hubs (LAX, JFK, LHR can add 20-30 min during peak), taxi time variance, weather delays. Padding makes on-time-arrival statistics look better. So a flight that “arrives 20 minutes early” is often arriving on the actual cruise + overhead time, not bonus.

What about polar routes?

Modern jets cross polar regions for shortest paths between northern hemisphere cities. ETOPS-certified aircraft (twin-engine planes certified for extended over-water operations) fly Toronto-Hong Kong over the North Pole. Polar routes save significant flight time vs equatorial routings. Earlier era (pre-1990s), regulations required twin-engine planes stay closer to alternate airports; trans-polar was four-engine territory only.

Home & Life · Free tool

Flight Time Calculator

Calculate great-circle flight durations with taxi buffer for 50+ airports instantly. Distance in km/miles, free online.

Updated June 2026

FromTo

Distance

5,540 km

3,442 miles

Estimated flight time

7h 1m

Cruise 850 km/h + 30 min buffer

Route notes

Standard

No dateline crossing

Estimates only — actual flight time varies with winds, routing, and ATC. Great-circle distance via the Haversine formula.

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What it does

Flight time between two airports is dominated by great-circle distance (the shortest line on Earth's surface between two points, which appears curved on flat maps but is straight on a globe) divided by typical jet cruise speed. Standard commercial jets (Boeing 737, Airbus A320, Boeing 777, A350): cruise around 540 mph (870 km/h) true airspeed. Adjust for: takeoff + landing overhead (~30 min total), headwind / tailwind (eastbound flights are typically faster due to jet stream; westbound slower; difference can be 15-30%), routing detours (great-circle might cross restricted airspace; actual route adds 5-10%). Result: NYC to London great-circle is 3,470 mi / 5580 km; actual flight time is 6:30-7:00 eastbound (with tailwinds), 7:30-8:00 westbound (with headwinds).

The calculator takes origin and destination airports (or coordinates), then outputs: great-circle distance in miles + km, estimated flight time at typical jet cruise (with takeoff/landing overhead), and time-of-day arrival estimate based on time zone difference. Useful for: travel planning where you need to estimate jet lag and connection feasibility, comparison shopping (sometimes shortest-distance flight isn't cheapest or fastest if connections are involved), and curiosity / travel learning. Real flight schedules published by airlines should be used for actual booking — they account for current- day winds, runway congestion, and specific aircraft performance.

Why actual flight times differ: (1) Jet stream (predictable westerly winds in Northern Hemisphere): adds 30-60 min eastbound transatlantic; subtracts same westbound. (2) Aircraft type — 777 cruises slightly faster than 737. (3) Routing — NYC-Tokyo great-circle goes over Alaska / Russia; actual flights detour for fuel stops, ETOPS rules, or political airspace restrictions. (4) Air traffic control — holding patterns, congestion at major hubs adds 10-30 min unpredictably. (5) Block time (gate-to-gate, what airlines schedule) includes taxi, takeoff, climb, cruise, descent, landing, taxi to gate. The calculator estimates cruise + 30 min overhead; airlines pad an additional 15-30 min for buffer (which is why flights often arrive “early” — they finished before the padded scheduled time). For booking decisions, refer to airline-published schedules; for general curiosity, calculator estimates are accurate within ~10%.

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How to use it

Pick origin airport (search by IATA code or city).
Pick destination airport.
Read great-circle distance in miles and km.
Read estimated flight time including takeoff/landing overhead.
Adjust expectations: eastbound flights are faster than westbound.

When to use this tool

Travel planning — estimating jet lag and connection feasibility.
Trivia / curiosity about flight distances and durations.
Educational — understanding why actual schedules vary by direction.
Multi-leg trip planning — summing flight times across connections.
Quick sanity check on airline-published times.

When not to use it

Actual booking decisions — use airline-published schedules with current-day data.
Private jet flight planning — different cruise speeds and routing rules.
Helicopter / regional turboprop — different speed assumptions.
Specific arrival-time planning — airline schedules pad for ATC delays.

Common use cases

Onboarding a colleague who needs the same calculation/conversion
Verifying a number or output before passing it on
Quick calculation during a typical workday
Pre-decision sanity-check on inputs and outputs

Frequently asked questions

Why does flight time differ by direction?: Jet stream — strong westerly winds at cruise altitude in the Northern Hemisphere. Eastbound transatlantic flights ride this tailwind: NYC-London is typically 6:30-7:00. Westbound flights face headwind: London-NYC is 7:30-8:00 (sometimes 8:30 with strong headwinds). Same airline, same aircraft, same route — direction matters dramatically. The difference is consistent (always favoring eastbound) but magnitude varies seasonally.
How fast do commercial jets fly?: Modern commercial jets cruise at 540-560 mph (870-900 km/h) true airspeed at typical cruise altitude (35,000-40,000 ft). Boeing 747, 777, A350: ~570 mph. Boeing 737, A320: ~540 mph. Regional jets (CRJ-700, Embraer 175): ~500-520 mph. Mach 0.78-0.85 typical (subsonic). Concorde was supersonic at Mach 2 but retired in 2003; Boom Supersonic working on Mach 1.7 jets for late 2020s commercial use.
What's great-circle distance?: Shortest distance between two points on a sphere. On Earth, looks curved on flat maps but straight on a globe. NYC to Tokyo great-circle goes OVER Alaska / Russia (looking at a globe makes this obvious). Latitude lines are NOT great circles (except the equator); they curve relative to actual shortest path. Modern jets fly close to great-circle routes; older flights followed political airspace and refueling stop constraints.
How accurate is the calculator?: Within ~10% of actual block time. Sources of variance: jet stream (±15-30%), routing detours, ATC delays, aircraft type variance. For booking decisions, use airline schedules. For general curiosity, calculator is fine. Caveat: calculator typically uses 540 mph cruise; some routes (high-altitude over polar regions) actually fly slightly faster due to stronger stratospheric winds.
Why are scheduled times longer?: Airlines pad scheduled times by 15-30 min beyond actual cruise + overhead time. Reasons: ATC delays at busy hubs (LAX, JFK, LHR can add 20-30 min during peak), taxi time variance, weather delays. Padding makes on-time-arrival statistics look better. So a flight that “arrives 20 minutes early” is often arriving on the actual cruise + overhead time, not bonus.
What about polar routes?: Modern jets cross polar regions for shortest paths between northern hemisphere cities. ETOPS-certified aircraft (twin-engine planes certified for extended over-water operations) fly Toronto-Hong Kong over the North Pole. Polar routes save significant flight time vs equatorial routings. Earlier era (pre-1990s), regulations required twin-engine planes stay closer to alternate airports; trans-polar was four-engine territory only.

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