Flight Time and Distance Calculator Between Two Airports

How to use it

Type the code, name or city of the Departure airport, for example IST or Istanbul, then click the airport you want. Press Enter to take the first match.
Do the same for the Arrival airport.
Check the Cruise speed (km/h), the Taxi, take-off and landing (min) and Climb and descent (min) allowances and the Travel date. The defaults are 830 km/h, 30 minutes, 20 minutes and today.
Read the route summary, the flight time and the Time difference on the travel date. If an airport has no city within 100 km, type its UTC offset in the box that appears.

How the distance and the time are found

The distance is the great-circle distance, the shortest path over the surface of the Earth. The page uses the haversine formula with the mean Earth radius, R = 6,371.0088 km: the mean radius (2a + b) / 3 of the WGS 84 ellipsoid.

The same two airports are also measured on the WGS 84 ellipsoid with Vincenty's inverse formula (1975), which takes the flattening of the Earth into account. The two distances differ by a fraction of one per cent, and the page shows both.

The flight time is a planning estimate. It adds the taxi, take-off and landing allowance (G) and the climb and descent allowance (C) to the distance (d) divided by the cruise speed (v): t = G + C + d ÷ v × 60 minutes. The midpoint is the point halfway along the great circle.

a = sin²(Δφ/2) + cos φ₁ · cos φ₂ · sin²(Δλ/2),   c = 2 · atan2(√a, √(1 − a)),   d = R · c,   t = G + C + d ÷ v × 60

What the estimate assumes and what it leaves out

This tool is for training and planning practice, not for flight. A real flight uses the operator's flight plan and approved data.

The cruise speed (830 km/h by default) is an assumption. Boeing's airport planning document for the 737 MAX gives only the long-range cruise setting ('CRUISE MACH = LRC'), not a speed, so no published figure was used. Set the speed you expect for your aircraft or airline.

The taxi, take-off and landing allowance (30 minutes by default) and the climb and descent allowance (20 minutes by default) are assumptions too. Not included in the estimate:

Winds: a headwind or a tailwind can add or save many minutes on a long route.
Routing: a real route follows airways and avoids restricted airspace, so it is longer than the great circle.
Departures, arrivals, holding and air traffic control delays.
Airline schedules, the time at the gate and the actual climb and descent profile of the aircraft.

Time zones and daylight saving

Each airport takes the IANA time zone of the nearest city in the GeoNames city list, when that city is within 100 km. The IANA Time Zone Database records the history of local time for many locations; its zone1970.tab lists the zones whose civil times have agreed since 1970.

The UTC offset of that zone is read for the travel date, so daylight saving is respected. On 2026-11-10 New York is on UTC-5 (standard time since 2026-11-01) and Istanbul is on UTC+3 all year, so the difference is 8 hours. On 2026-03-10 New York is already on daylight time, and the difference is 7 hours.

When no city lies within 100 km, the page shows the time zone as unknown and uses the UTC offset you type, in hours from -14 to +14.

City time zones: GeoNames, CC BY 4.0.

Example: Istanbul Airport to London Heathrow

Choose IST and LHR, keep the cruise speed at 830 km/h, the allowances at 30 and 20 minutes, and the travel date at 2026-11-10. The page then shows:

Route summary: IST to LHR: 2,487 km great circle, estimated 3 h 50 min. Great-circle distance: 2,487 km. Ellipsoidal distance: 2,493 km, a difference of -0.22 %.

Flight time: 30 + 20 + 2,487 ÷ 830 × 60 = 229.8 min, shown as 3 h 50 min. Midpoint: 47.30, 15.53. Time difference: London is on UTC+0 and Istanbul on UTC+3, so the arrival time is 3 h behind (-3 h).

Frequently asked questions

Does the estimate match the time in an airline timetable?

Not exactly. Airline timetables include the block times the operator plans, which change with the season, the winds and the route. Use the timetable to plan your day, and this estimate to compare routes and to get a rough idea.

Why is the ellipsoidal distance a little different from the great-circle distance?

The Earth is flattened at the poles, so the shortest path on the real ellipsoid (Vincenty's formula on WGS 84) is a little different from the path on a sphere. For the routes on this page the difference is a fraction of one per cent.

Why does the page show an airport's time zone as unknown?

The time zone comes from the nearest city in the GeoNames list, and only when that city is within 100 km. Some airports, often remote ones, have no listed city that close. Type the UTC offset of the airport in hours, and the page uses it for the time difference.

Does daylight saving change the time difference?

Yes. The offset of each zone is read for the travel date, so a route can change its difference twice a year. New York and Istanbul are 8 hours apart in November and 7 hours apart in March, because New York uses daylight saving between March and November.

Can I use this tool to plan a real flight?

No. The tool is for training and planning practice. A real flight uses the operator's flight plan, approved performance data, the weather and the air traffic clearances. Never use these figures for flight planning.

Where do the airport codes come from?

The airports come from the OurAirports data set. IATA assigns the three-letter codes used for tickets and baggage, and ICAO assigns the four-letter location indicators used by pilots and air traffic control. Some airports have only one of the two codes.

Why is the cruise speed 830 km/h?

It is an assumption. The Boeing airport planning document for the 737 MAX gives only the long-range cruise setting, not a speed in km/h, so 830 km/h is a planning value. Change it to the speed you expect.

Sources

Figures and text last checked on Tuesday, November 10, 2026.