Free Map Distance Calculator
Click two or more points on the map to measure the straight-line (great-circle) distance between them. Results are shown in kilometres, miles, and nautical miles using the Haversine formula.
Click on the map to place waypoints. Each new point extends the route and the total distance updates instantly.
Click the map to place your first point.
Quick answer
To measure distance on a map, click your start point and then your end point — the tool draws a line and calculates the great-circle distance using the Haversine formula, which accounts for Earth's curvature. The result is the shortest over-the-surface distance, sometimes called as-the-crow-flies distance. Real road or flight distances will be longer. Add intermediate waypoints to measure multi-leg journeys.
Formula & method
d = 2R · arcsin(√(sin²(Δφ/2) + cos φ₁ · cos φ₂ · sin²(Δλ/2)))
- d — Great-circle distance (km)
- R — Earth's mean radius, 6,371 km
- φ₁, φ₂ — Latitudes of the two points (radians)
- λ₁, λ₂ — Longitudes of the two points (radians)
Haversine formula. R = 6,371 km (Earth's mean radius), φ = latitude in radians, λ = longitude in radians, Δ = difference between the two points.
Examples
- Input
- New York (40.7128° N, 74.0060° W) → London (51.5074° N, 0.1278° W)
- Result
- 5,570 km (3,461 miles)
- Why
- Applying Haversine with Δφ ≈ 0.1882 rad and Δλ ≈ 1.2856 rad gives d ≈ 5,570 km. This is the shortest surface path (great-circle route), not the actual flight distance which varies by routing.
- Input
- Tokyo (35.6762° N, 139.6503° E) → Sydney (33.8688° S, 151.2093° E)
- Result
- 7,823 km (4,861 miles)
- Why
- The Haversine calculation across 69.5° of latitude difference and 11.6° longitude difference yields ≈ 7,823 km. Tokyo to Sydney flights often follow a similar but slightly longer route.
- Input
- Paris (48.8566° N, 2.3522° E) → Berlin (52.5200° N, 13.4050° E)
- Result
- 878 km (546 miles)
- Why
- With Δφ ≈ 0.0651 rad and Δλ ≈ 0.1920 rad the Haversine formula gives ≈ 878 km. Road distance is roughly 1,050 km due to highway routing.
- Input
- Trailhead (47.60° N, 122.33° W) → Summit (47.74° N, 121.87° W) → Lake (47.81° N, 121.91° W)
- Result
- Leg 1 ≈ 40 km, Leg 2 ≈ 8 km, Total ≈ 48 km
- Why
- Each leg is calculated separately with Haversine and summed. Actual trail distance will be greater due to elevation changes and trail switchbacks.
When to use this tool
- Estimating travel distances between cities or landmarks for trip planning.
- Calculating straight-line property boundaries, exclusion zones, or delivery radius.
- Academic or engineering purposes requiring precise great-circle distances.
- Measuring multi-leg routes or hiking paths where you want the sum of segment distances.
Common mistakes
- Confusing great-circle (straight-line) distance with road or flight distance — road distances are typically 20–40% longer.
- Expecting nautical miles to equal kilometres — 1 nautical mile = 1.852 km.
- Clicking too hastily at low zoom levels — zoom in before placing a point for metre-level accuracy.
- Forgetting that latitude comes first in most coordinate formats (lat, lng) but some tools expect (lng, lat).
Frequently asked questions
What is the difference between great-circle distance and driving distance?
Great-circle (as-the-crow-flies) distance is the shortest path over Earth's curved surface between two points. Road distance follows actual roads and can be 20–50% longer. For flights, actual routes deviate from great-circle paths due to wind, air-traffic corridors, and politics.
How accurate is the Haversine formula?
The Haversine formula assumes Earth is a perfect sphere of radius 6,371 km. Real Earth is an oblate spheroid, so errors can reach ±0.3%. The Vincenty formula is more accurate but Haversine is sufficient for most practical purposes.
Can I measure in feet or meters?
1 km = 1,000 m and 1 mile = 5,280 feet. Use the km result and multiply by 1,000 for metres, or multiply miles by 5,280 for feet.
What is a nautical mile?
One nautical mile is exactly 1.852 km (1,852 m), originally defined as one arc-minute of latitude. It is the standard unit of distance in aviation and maritime navigation.
Can I add more than two points?
Yes — click additional points on the map to add waypoints. The tool calculates each leg's distance and sums them for a total route distance.
How do I reset the measurement?
Click the Clear button to remove all points and start a new measurement.
Sources & references
External references open in a new tab. We are independent and not affiliated with these organizations.
- ✓ Free to use
- ✓ No sign-up required
- ✓ Runs entirely in your browser — nothing is uploaded.
- ✓ Formula and method shown above
Provided “as is” for general information only — results may be inaccurate, so verify before you rely on them. No warranty; use at your own risk.
Built and reviewed by HIFreeTools against the formula shown above and any authoritative references cited on this page. See our methodology and editorial standards.
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