Distance Calculator
Calculate the distance between major cities worldwide. See great-circle distance in km and miles, estimated flight time, and time zone difference for 50+ global cities.
Distance
344km
213miles
Flight Time (approx.)
0h 24m
at 800 km/h cruise speed
Time Zone Difference
+1 hours
Journey Summary
From:London, UK
To:Paris, France
Great circle distance:344 km (213 mi)
Flight time estimate:0h 24m
Flight time estimates assume constant cruise speed and do not account for takeoff, landing, taxiing, or air traffic routing. Actual flight times will be longer and vary by season. Great circle distance is calculated as the shortest path between two points on a sphere.
How the Distance Calculator Works
Pick two cities from the dropdowns. The calculator looks up each city's latitude and longitude, runs them through the Haversine formula to compute the great-circle distance (the shortest path along the surface of the Earth, which on a sphere is an arc rather than a straight line), and returns the answer in kilometres and miles. It also estimates flight time using a typical commercial cruising speed and shows the time-zone difference.
The Haversine formula treats the Earth as a sphere with radius 6,371 km. Real distances are typically within 0.5% of the spherical answer for any practical city-to-city distance, so the slight oblateness of the Earth doesn't matter for trip planning. What does matter is that great-circle distance is always less than or equal to the road or rail distance, often substantially less. Driving from London to Edinburgh is about 660 km via M1 and A1, but the great-circle distance is only 530 km.
Why Flight Distances Look Curved on a Map
Most flight maps are drawn on a Mercator projection, which stretches high latitudes horizontally and squashes them vertically. The shortest path between two points on a sphere, when drawn on a Mercator map, looks curved (a 'great circle arc') because the underlying flat-paper geometry doesn't match the curved Earth. London to Tokyo is shorter going north over Russia and the Arctic than across India, even though the India route looks shorter on a flat map.
Pilots fly great-circle routes when winds and airspace allow, because every kilometre saved is fuel saved. North Atlantic flights between Europe and North America commonly pass over Greenland or Iceland for this reason. The estimated flight time in this calculator assumes a 800 km/h average ground speed (cruise speed minus typical headwind allowance) and ignores taxi, takeoff, climb, descent and landing, so real journey times are typically 30-60 minutes longer than the calculator shows.
Distances Between Some Familiar City Pairs
| From | To | Great-circle (km) | Flight time approx |
|---|---|---|---|
| London | New York | 5,570 | 7h 0m |
| London | Paris | 344 | 0h 25m airborne |
| London | Tokyo | 9,560 | 12h 0m |
| London | Sydney | 16,990 | 21h 15m |
| New York | Los Angeles | 3,940 | 4h 55m |
| Singapore | Sydney | 6,290 | 7h 50m |
| Cape Town | Cairo | 7,260 | 9h 5m |
What People Use the Distance Calculator For
Booking flights and gauging whether a destination is realistic for the time available. Calculating air mileage for frequent-flyer programmes (most use great-circle distance as the basis). Settling pub-quiz arguments about which city is further from somewhere else. Sense-checking quoted travel times: a 4-hour flight time from London suggests roughly 3,200 km of distance, which fits Madrid or Cairo and rules out anything in Asia.
If you're planning a UK route specifically and want walking time rather than flight time, the [Walking Time Calculator](/walking-time-calculator) uses real OSM road geometry rather than great-circle distances. For cross-timezone scheduling alongside the distance, the [Timezone Converter](/timezone-converter) handles the daylight-saving variations that make 'time difference' a moving target.
Frequently Asked Questions
Why is the distance shorter than driving distance?
Great-circle distance is the shortest path along the Earth's surface, ignoring roads, mountains and political borders. Driving distance has to follow actual roads, which add detours, switchbacks for hills, and bypasses around lakes or restricted zones. For long flat routes the difference is small (London to Manchester is 263 km flat, 320 km by road). For routes around bodies of water or through mountainous terrain, the difference can be large.
How accurate is the flight time estimate?
Within an hour for typical commercial routes, but always shorter than the published flight time. The calculator uses 800 km/h average ground speed, which accounts for cruise plus typical headwinds. Published flight times include taxi, takeoff, climb, descent, holding, and landing, plus tailwinds or headwinds specific to the route. London to New York is roughly 6h 30m airborne but published as 7h 30m to 8h.
What is the Haversine formula?
It's a trigonometric formula for great-circle distance on a sphere. Given two latitude/longitude pairs, it computes the angular distance between them, then multiplies by the Earth's radius to get a length. It's been the standard for navigation since the 19th century and is accurate to within 0.5% for any real-world distance, which is more than good enough for flight planning at the resolution of an airport runway.
Why are some flights between European cities longer than the great-circle distance suggests?
European airspace is heavily congested, and many flights are routed around restricted military zones or along published airways rather than direct great-circle paths. Short-haul flights (under 1,000 km) also spend a higher proportion of total time on takeoff and landing, so the airborne portion is a smaller share of the total.
Can I use this for non-flight distances?
Yes, the great-circle distance is purely geometric. It applies to any straight-line measurement on the Earth's surface, including ship routes, missile trajectories, and 'as the crow flies' references in everyday speech. For walking or driving distances along actual roads, you'd want a routing service rather than a great-circle calculation.