Airport Distance Calculator
Estimate distance between two latitude/longitude points.
About the Airport Distance
This measures the great-circle distance between any two points on earth — the shortest path across a curved surface, which is what an aircraft actually follows. Enter the latitude and longitude of two airports or cities and you get the air miles between them. It is not driving distance, and it is not the mileage an airline credits you, though it is usually very close to the latter.
How to use it
- Enter the latitude and longitude of your departure point.
- Enter the coordinates of your destination.
- Use negative values for south of the equator and west of Greenwich.
- Read the distance in miles and kilometres.
The formula
The haversine formula finds the distance along the surface of a sphere. It stays accurate for very short distances, which is where the simpler spherical law of cosines breaks down.
a = sin²(Δφ/2) + cos φ₁ · cos φ₂ · sin²(Δλ/2)
d = 2R · atan2(√a, √(1−a))
Where φ is latitude, λ is longitude, Δ is the difference between the two points, and R is the earth's mean radius — 3,959 miles or 6,371 km. Because the earth is very slightly flattened rather than a true sphere, results can differ from an ellipsoidal calculation by up to about 0.3%.
Worked examples
| Route | From | To | Great-circle distance |
|---|---|---|---|
| Spokane → Seattle | 47.62°N, 117.53°W | 47.45°N, 122.31°W | 223 mi / 359 km |
| New York → London | 40.64°N, 73.78°W | 51.47°N, 0.45°W | 3,443 mi / 5,541 km |
| Los Angeles → Tokyo | 33.94°N, 118.41°W | 35.55°N, 139.78°E | 5,476 mi / 8,813 km |
| Sydney → Singapore | 33.95°S, 151.18°E | 1.36°N, 103.99°E | 3,912 mi / 6,295 km |
Notice the Sydney route crosses the equator, so its latitudes have opposite signs. Getting a sign wrong is the single most common reason a result comes out thousands of miles off.
Common mistakes
- Dropping the minus sign. West longitude and south latitude are negative. New York is −73.78, not 73.78 — enter it positive and you will get a distance to somewhere in China.
- Entering degrees, minutes and seconds. This expects decimal degrees. 47°37'12" is 47.62, not 47.3712.
- Swapping latitude and longitude. Latitude comes first and never exceeds 90. If your first number is above 90, the pair is the wrong way round.
- Expecting it to match your driving app. Roads bend around terrain and property. A great-circle line ignores all of it.
Terms explained
- Great-circle distance
- The shortest route between two points on a sphere. On a flat map it looks like a curve, which is why flights to Europe appear to arc north over Greenland.
- Haversine formula
- The standard method for great-circle distance. It is numerically stable for small separations, unlike the simpler cosine version.
- Decimal degrees
- Coordinates as a single number with a fraction, such as 47.62. Divide minutes by 60 and seconds by 3600 to convert.
- Nautical mile
- One minute of latitude, about 1.15 statute miles. Aviation and shipping use it because it maps directly onto the coordinate grid.
Common questions
- Why is it different from driving distance?
- Roads follow terrain, property lines and existing towns. This is the direct line across the earth's surface, so it is always shorter — often by 20-40% on a road trip.
- Where do I find the coordinates for an airport?
- Any mapping service shows latitude and longitude if you drop a pin on the terminal. Aviation databases also publish them for every ICAO and IATA code.
- Do planes actually fly this route?
- Roughly. Real routes bend for airspace restrictions, weather, and the jet stream — which is why a westbound Atlantic crossing usually takes longer than the same trip eastbound.
- Is this the distance airlines use for frequent-flyer miles?
- Most award programmes credit great-circle distance between airports, so this is usually within a few miles of what you will be awarded.
- How accurate is it?
- The formula is exact for a sphere. The earth is slightly flattened at the poles, so a true ellipsoidal calculation can differ by up to about 0.3% — roughly 10 miles on a 3,500-mile flight.
- Can I use it for short distances?
- Yes. Haversine is specifically chosen because it stays accurate down to metres, where other great-circle formulas lose precision.
- What about altitude?
- Ignored, and it barely matters. Cruising at 35,000 feet adds about 0.17% to the path — under 6 miles on a transatlantic flight.