Distance between cities – how far is it?

"How far is it from Paris to Rome?" usually means one of two things: how long a drive or a train ride is, or how far apart the two cities really are. This page answers the second question, the distance as the crow flies, which is also the number airlines, pilots, radio amateurs and geography teachers use. Pick the first city from the list as you type, then the second, and the panel shows the distance in your chosen unit with the two others beside it, the direction you would head from the first city, and an estimate of the flight time. Keep adding cities, up to ten, and a distance table appears with every pair: handy for planning a trip with several stops, comparing where to hold a meeting, or checking a school assignment. The total along the list tells you how far a round of visits in that order is, and the table names the two cities that are farthest apart and the two that are closest. The line on the map follows the shortest path on the globe, which is why a flight from Europe to North America curves north over Greenland on a flat map. Places that are not in the city list can be added by clicking on the map.

How to use it

1. Type the first city and pick it from the list, then do the same for the second one.
2. Read the distance, the direction and the estimated flight time in the panel.
3. Add more cities, up to ten, to get a distance table of every pair.
4. Download the table as CSV, share the link, or export the cities and lines as KML or GeoJSON.

How accurate is it?

Exact on the ellipsoid, from city centre to city centre

The distance is the geodesic on the WGS84 ellipsoid, calculated with GeographicLib, so the number between the two points is right to well under a metre. The points come from GeoNames and usually mark the historic centre or the town hall. A big city can be 30 to 50 km across, so the distance to a suburb or an airport can differ from the centre-to-centre figure by that much. For an exact start or finish, click the place on the map or drag the numbered marker.

Why it differs from other calculators

Many sites use the haversine formula on a perfect sphere with a radius of 6,371 km. That is quick, but the Earth is flattened at the poles, so a sphere is off by up to about 0.5 %: some 30 km on a 6,000 km flight. Others measure on a flat web map, which can be wrong by far more over long distances. Small differences can also come from the point each site uses for a city.

How the flight time is estimated

The flight time is the straight-line distance at an average 800 km/h plus 30 minutes for take-off, climb, approach and landing, rounded to five minutes. That matches typical airliner schedules within about half an hour, but real times depend on the jet stream (eastbound flights over the Atlantic are often an hour faster than westbound), the route around restricted airspace, and the time spent taxiing.

Good to know

Driving distance is longer

Roads, rivers, mountains and coastlines make the drive longer than the straight line, typically by 20 to 40 % on land and much more where a ferry or a detour around a bay is needed. Use the straight-line figure to compare places or to estimate, and a route planner for the actual drive.

Cities with the same name

There are dozens of places called Springfield, Paris or San José. The list shows the country next to each name and puts the biggest place first; check the country in the list of places below the panel before you trust the result.

Shortest path, not a straight line on the map

On the map the shortest path looks curved, and a straight line drawn with a ruler on the map is longer. The direction you leave in also changes along the way: from London to Los Angeles you start towards the north-west and arrive heading south-west.