Air Distance Calculator
Air distance is the shortest path between two points over the surface of the Earth: the great-circle route an aircraft would follow in a perfect world with no wind, no air-traffic corridors and no climb or descent. The Air Distance Calculator below measures it from latitude and longitude coordinates using the haversine formula, and returns the distance in kilometres, miles and nautical miles, plus a cruise flight-time estimate and the initial compass bearing.
Because the tool takes raw coordinates instead of place names, it works for any two points on the planet: two airports, a trailhead and a summit, a ship’s position and the nearest port. If all you have is a place name, the short section further down on finding coordinates shows how to lift them from any map app in seconds.
The flight time is a cruise-only estimate at 560 mph: real scheduled times add climb, descent, routing and wind. The bearing is the initial heading on departure; on a great-circle route the heading changes continuously along the way.
Quick Answer
The worked example at a glance
The transatlantic route above is the standard test case for great-circle tools, and it shows why the route on a flat map looks wrong: the shortest path bows north toward the North Atlantic, which is why the departure heading is north-east even though London sits at almost the same longitude band as the US east coast destinations people picture as “straight across.”
The haversine formula, explained
The haversine formula finds the central angle between two points on a sphere from their coordinates, then turns that angle into a distance with the Earth’s radius. It is the formula the reference implementations in Chris Veness’s latitude and longitude scripts use, and it is the standard answer to “how far apart are these two coordinates” in aviation and maritime work.
Two accuracy notes, stated plainly. First, the Earth is not a perfect sphere: it bulges at the equator (radius about 6,378 km) and flattens at the poles (about 6,357 km), so any spherical formula carries an error of up to roughly 0.5%. For the worked example above, that is at most about 28 km against a 5,540 km route, irrelevant for flight planning, drone range checks or curiosity, and the reason survey-grade work uses ellipsoidal models such as WGS84 instead. Second, the most common real-world error is not the formula at all: it is swapped or sign-flipped coordinates. Latitude comes first, north and east are positive, south and west are negative. Enter a west longitude as positive and the tool will faithfully measure to a point in the wrong hemisphere.
Worked example: New York JFK to London Heathrow
The calculator is pre-filled with this route, and every figure below is what it returns.
| Figure | Value |
|---|---|
| Point 1: New York JFK | 40.6413, -73.7781 |
| Point 2: London Heathrow | 51.4700, -0.4543 |
| Distance in kilometres | 5,540.01 km |
| Distance in miles | 3,442.40 miles |
| Distance in nautical miles | 2,991.37 NM |
| Initial bearing | 51° (NE) |
| Flight-time estimate at 560 mph cruise | 6h 9m |
Cross-check with a second route: Los Angeles (34.0522, -118.2437) to New York City (40.7128, -74.0060) returns 3,935.75 km or 2,445.56 miles, in line with published US transcontinental references. One reason your figure may differ slightly from a number quoted elsewhere: coordinates. A guide using London city centre (51.5074, -0.1278) instead of Heathrow will report a route a few kilometres different, and both are “correct” for the points entered. Encyclopaedia Britannica’s entry on the great circle explains the underlying geometry: the great circle is the largest circle that can be drawn on the sphere, and its arc is by definition the shortest surface path.
Where to get coordinates for any two places
Search the place name with the words “latitude longitude” and most map services will show the pair, or open the place in a map app, press and hold (or right-click) the exact spot, and read the decimal degrees from the pin details. Airports are the easy case: their published coordinates are stable and precise, like JFK at 40.6413, -73.7781. For a field location, a phone’s compass or GPS app reads your current coordinates directly. Keep four or more decimal places: the fourth decimal is worth about 11 metres, so rounding to two decimals can move a point by a kilometre and quietly change a short-distance result.
Air distance or road distance?
They answer different questions, and using one where you need the other is the classic planning error. Air distance is the floor: no real journey can be shorter. Road distance follows the network and typically runs 20 to 50% longer on the same pair of points.
Use air distance when
You are planning a flight, a drone survey, a radio link or a boat passage; estimating fuel or range; or comparing how far apart two places fundamentally are. The actual distance calculator covers the related straight-line measurement questions on the ground.
Use road distance when
You are driving, quoting a delivery route, or budgeting road fuel and time. For range questions that follow from a distance figure, the fuel distance calculator turns distance into fuel terms once you know which kind of distance you actually have.
NOAA’s Ocean Service makes the same point from the navigation side in its great circle route explainer: ships and aircraft follow great-circle tracks because they are shorter, then adjust them for weather, currents and traffic, which is why the distance actually travelled is always a little more than the number on this page.
What competing calculators miss
We checked the top-ranking great-circle and flight-distance tools before rebuilding this page.
Winning move 1: coordinates, not a name database. Airport-name tools are pleasant until your point is not an airport. This tool measures any two coordinate pairs, including places with no name at all, which is what drone operators, sailors and surveyors actually need.
Winning move 2: bearing and flight time on the same result. Formula-first rivals such as the haversine pages at CalculatorsHub and CalcTo.work return a distance and stop. Pilots and planners need the next two numbers (which way do I head, and how long at cruise) and both are here, each labelled with its limits: initial bearing only, cruise-only time.
Winning move 3: all three units, every time. Several tools output a single unit or bury nautical miles, the unit aviation actually plans in. The headline unit is your choice, and the full three-unit line appears under every result so nothing needs converting by hand. The reference-grade formula pages, Movable Type among them, document the maths beautifully but are written for developers; this page keeps their exact formula and adds the plain-English coordinate guidance a traveller needs.
Frequently asked questions
Air distance is the shortest distance between two points measured along the surface of the Earth, following a great-circle route. It is the distance an aircraft would fly in a perfect world with no wind, no air-traffic routing and no climb or descent, and it is always shorter than the road distance between the same places.
Accurate to roughly 0.5% for practical purposes. The Earth is slightly flattened at the poles, so a spherical formula cannot match an ellipsoidal model exactly. On a 5,540 km route the difference is under 30 km, which is why haversine is the standard for flight planning and general use while survey-grade work uses WGS84 ellipsoidal maths.
It uses 6,371 km, the Earth’s mean radius, the standard value in haversine references. The equatorial radius is about 6,378 km and the polar radius about 6,357 km; the mean value keeps errors balanced across all latitudes.
Airlines publish distances from their own city-pair tables, and actual flights run longer than the great-circle line because of departure and arrival procedures, air-traffic corridors and winds. This calculator returns the pure geometric distance between the coordinates you enter, which is the correct baseline both figures are built from.
A nautical mile is 1.852 km, defined as one minute of latitude. Aviation and maritime navigation use it because it ties distance directly to the coordinate grid: one nautical mile is roughly one minute of arc along a meridian, which makes chart work and position reporting simple.
Not directly. This tool takes coordinates so it can measure any two points on Earth, including places with no airport or no name. Look the place up in a map app, press and hold the spot to read its latitude and longitude in decimal degrees, and enter those numbers here.
The initial bearing is the compass heading to follow when departing along the great-circle route. Because the route curves relative to the map, the heading changes continuously along the way, so this is the departure heading only. It is useful for pilots, sailors and antenna alignment.
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References
- Chris Veness, Movable Type Scripts, “Calculate distance and bearing between two latitude/longitude points” – the reference haversine and initial-bearing formulas this calculator implements, with worked code. Movable Type: Latitude and Longitude Calculations. Accessed October 2026.
- Encyclopaedia Britannica, “Great circle” – the geometry of the largest circle on a sphere and why its arc is the shortest surface path between two points. Britannica: Great Circle. Accessed October 2026.
- National Oceanic and Atmospheric Administration, Ocean Service, “What is the great circle route?” – why ships and aircraft plan along great-circle tracks and then adjust for weather and traffic. NOAA Ocean Service: Great Circle Route. Accessed October 2026.
- Federal Aviation Administration, “Pilot’s Handbook of Aeronautical Knowledge” – the standard FAA reference for navigation, great-circle routes and flight planning concepts. FAA: Pilot’s Handbook of Aeronautical Knowledge. Accessed October 2026.
- Federal Aviation Administration, “Aeronautical Information Manual” – official guidance on navigation aids, routes and the units, including nautical miles, used in flight operations. FAA: Aeronautical Information Manual. Accessed October 2026.