Flight Distance Calculator
Find the great-circle distance between any two airports or coordinates, with the course to fly, the midpoint, an estimated flight time and CO2 per passenger.
Hamad International Airport · OTHH · Qatar
London Heathrow Airport · EGLL · United Kingdom
Airliners average about 460 kt (530 mph, 850 km/h).
All three are always shown.
Added once per flight (each leg).
The ellipsoid is what GPS uses; the two differ by under 0.5%.
How your flight distance is worked out
Shortest path over a round Earth, then distance ÷ speed.
- 1
Two points
DOH 25.27°, 51.61°LHR 51.47°, −0.46°(lat, lon)
- 2
Haversine angle
Δlat 26.20°Δlon 52.07°= 47.14°
- 3
Distance
47.14° of a6,371 km radius= 5,241 km= 2,830 nm
- 4
Flight time
2,830 nm ÷ 460 kt= 6h 09m+ 30 min taxi= 6h 39m
Read more: the formula, a worked example, CO2 method and notes
The calculator finds the shortest path between the two points over the Earth's surface (the great circle), converts it to nautical miles, kilometres and statute miles, then divides by your speed to estimate the flight time. With stops, each leg is worked out on its own and the legs are added up.
The formula
a = sin²(Δlat ÷ 2) + cos(lat1) × cos(lat2) × sin²(Δlon ÷ 2)
angle = 2 × asin(√a)
distance = angle (in radians) × Earth radius (6,371 km)
nautical miles = km ÷ 1.852 · statute miles = km ÷ 1.609344
initial course = atan2(sin Δlon × cos lat2, cos lat1 × sin lat2 − sin lat1 × cos lat2 × cos Δlon)
flight time = distance (nm) ÷ (cruise speed ± wind) + taxi and climb allowance
Worked example
Doha Hamad (DOH, 25.2731°N 51.6081°E) to London Heathrow (LHR, 51.4706°N 0.4619°W). The latitude difference is 26.1975° and the longitude difference is 52.07°. That gives a = 0.15988, so the angle at the Earth's centre is 2 × asin(√0.15988) = 0.82271 radians (47.14°). Times 6,371.0088 km, the distance is 5,241 km, which is 5,241.47 ÷ 1.852 = 2,830 nm or 5,241.47 ÷ 1.609344 = 3,257 miles.
The initial true course is 318° (north-west) and the final course on arrival is 283°. The midpoint is at 41°16.33′N 30°42.94′E, near Istanbul. At 460 knots the cruise takes 2,830.17 ÷ 460 = 6.15 hours (6h 09m); adding 30 minutes for taxi, climb and descent gives about 6h 39m.
CO2 per passenger: method and source
CO2e = great-circle km × 1.08 × factor for the distance band and cabin (× 1.7 with high-altitude effects)
Factors are the UK Government (DESNZ) greenhouse gas conversion factors for business travel by air, in kg CO2e per passenger-km, without the radiative forcing uplift. The 8% extra distance follows DESNZ guidance for indirect routing and holding. Bands are set by distance here: under 500 km uses the domestic factor, up to 3,700 km short-haul, and beyond that long-haul.
| Band | Economy | Premium | Business | First |
|---|
Doha to London is long-haul: 5,241.47 km × 1.08 × 0.0775 = 439 kg CO2e per economy passenger, or about 746 kg with high-altitude effects. A business seat takes more cabin space, so its share is higher.
Typical cruise speeds
| Aircraft type | Typical average speed |
|---|---|
| Long-haul jet (A350, 787, 777) | 460–490 kt |
| Short-haul jet (A320, 737) | 400–440 kt |
| Turboprop (ATR 72, Dash 8) | 250–280 kt |
| Light piston (Cessna 172) | 105–120 kt |
Why real flights are longer
- Airways, air-traffic routings and closed airspace bend the route away from the great circle.
- Jet streams make eastbound flights faster and westbound ones slower; airlines plan around the winds.
- Long twin-engine flights must stay within reach of diversion airports (ETOPS), which can add distance over oceans.
- Airline schedules are gate to gate and add time for busy airports.
Airport positions are from OurAirports (public domain), large and medium airports with an IATA code. Courses are true, not magnetic. CO2 factors are an estimate for an average flight, not your airline's exact figure; the per passenger-km values follow the UK Government (DESNZ) 2025 set but have not yet been checked against the official spreadsheet. Not for navigation.
Common questions
How far is it from Doha to London by air?
Along the great circle, Hamad International (DOH) to London Heathrow (LHR) is 5,241 km, which is 2,830 nautical miles or 3,257 statute miles. Real flights cover a little more because air-traffic routes, airways and weather detours are rarely perfectly straight.
What is great-circle distance?
It is the shortest path between two points on the surface of a sphere, following the curve of the Earth. On a flat map it looks curved, often bending towards the pole, which is why flights from New York to Hong Kong pass near the Arctic. Airlines use it as the starting point for route planning.
How is flight time estimated from distance?
Divide the distance by the ground speed, then add time for taxi, take-off, climb and descent. Doha to London is 2,830 nm; at 460 knots that is 6h 09m in cruise, and adding 30 minutes gives about 6h 39m. A headwind lowers the ground speed and adds time; a tailwind does the opposite.
What is the difference between nautical miles, miles and kilometres?
A nautical mile is exactly 1.852 km and is used in aviation and at sea because one nautical mile is about one minute of latitude. A statute mile is 1.609344 km. So 1,000 nm is 1,852 km or about 1,151 miles. The calculator shows all three at once.
Why does the heading change during a long flight?
On a great circle the true course changes as you go, except when flying due north, due south or along the equator. Doha to London starts on a course of about 318° (north-west) and arrives on about 283°. The calculator shows both the starting and the final course.
How much CO2 does a flight produce per passenger?
This calculator uses UK Government (DESNZ) conversion factors per passenger-km by distance band and cabin, with 8% added to the distance for indirect routing. For Doha to London in economy that is about 439 kg of CO2e per passenger, or about 746 kg including the extra warming effect of emissions at altitude.
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