Calculate the straight-line "as the crow flies" distance between two coordinates using the Haversine formula for accurate results.
The phrase "as the crow flies" refers to the shortest distance between two points — a straight line through the air, ignoring roads, terrain, and obstacles. This calculator uses the Haversine formula to compute that direct distance from any two sets of geographic coordinates.
This measurement is useful in many contexts: real estate (how far is a property from the city center), emergency services (response radius), logistics (straight-line vs actual route comparison), and general geographic curiosity. The result represents the absolute minimum distance between two locations on Earth's surface.
Enter the latitude and longitude of two points, and get the direct distance in miles, kilometers, and nautical miles. Compare this to the actual road distance to understand how much extra distance roads, terrain, and routing add to your journey. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation. By automating the calculation, you save time and reduce the risk of costly errors in your planning and decision-making process.
Road distances include detours, curves, and indirect routing. The as-the-crow-flies distance provides a baseline for comparison, helping you understand the efficiency of available routes. It's also the standard measurement for radio transmission range, property radius searches, and geographic analysis. Having a precise figure at your fingertips empowers better planning and more confident decisions.
Haversine: d = 2R × arcsin(√(sin²(Δφ/2) + cosφ1 × cosφ2 × sin²(Δλ/2))) Where R = 6,371 km, φ = latitude, λ = longitude
Result: 213 miles (343 km)
London (51.51°N, 0.13°W) to Paris (48.86°N, 2.35°E) is approximately 213 miles (343 km) as the crow flies. The actual driving distance via the Channel Tunnel is about 290 miles, showing that roads add roughly 36% to the direct distance.
Earth's surface is curved, so the shortest distance between two points follows a great circle — the intersection of the sphere with a plane passing through the center. The Haversine formula computes this arc distance accurately for most practical purposes.
The ratio of road distance to straight-line distance is called the route factor or circuity factor. Highways typically have a factor of 1.2–1.3, city streets 1.3–1.5, and mountainous roads 1.5–2.0. Understanding your route factor helps you estimate driving distances from straight-line measurements.
Straight-line distance is used in cell tower coverage planning, emergency response radius mapping, real estate proximity analysis, and environmental impact assessment zones. Insurance companies use it to determine property distance from coastlines and fire stations.
The Haversine formula is accurate to within 0.5% for any distance on Earth. For sub-meter precision needed in surveying and engineering, the Vincenty or Karney algorithms account for Earth's ellipsoidal shape.
It means the straight-line distance between two points, as if a crow flew directly from one to the other. It's the shortest possible distance across Earth's surface, ignoring all terrain and obstacles.
Typically 20–50% longer. In flat areas with grid roads, it may be only 20% more. In mountainous regions or areas with water bodies, road distance can be 50–100% more than straight-line.
On Earth's surface, yes. The great-circle route IS the shortest path between two points on a sphere. A true straight line through the Earth would be shorter but isn't physically traversable.
Google Maps: right-click any point to see coordinates. Apple Maps: drop a pin and tap to see coordinates. You can also search "latitude longitude of [city name]" online.
This calculator requires coordinates. To get coordinates for an address, use Google Maps or a geocoding service that converts addresses to lat/long pairs.
They actually DO follow straight lines on a globe (great circles). Flat map projections distort these paths into curves. A flight from New York to Tokyo appears to curve north on a flat map but follows the shortest path on a globe.