🌏 The other side of the Earth from Santo Domingo

Drop a line from Santo Domingo straight through the centre of the planet and it comes out at -18.4700, 110.1000 — the antipode. Flip the latitude sign and add 180° of longitude; the surface distance between the two points is half of a great circle, 20,015 km, which is the longest possible separation anywhere on Earth, and the line through the planet itself is the mean diameter, 12,742 km. Of the places we hold coordinates for, the one nearest to that antipode is Yogyakarta (Indonesia), 1,187 km away — which usually means the other side is open ocean.

How an antipode is calculated

Two antipodal points are related by a single rule: the latitude keeps its size and changes hemisphere, and the longitude moves half a turn around, so east becomes west and the figure is folded back into the −180° to +180° range if it crosses the dateline. For Santo Domingo at 18.47, -69.9 that gives -18.4700, 110.1000. The distance between the pair does not depend on where you start: measured along the surface it is always half of a great circle, about 20,015 km, and measured through the planet it is the diameter, about 12,742 km. Any straight line you draw through the centre of the Earth and out the other side ends at the antipode, which is also why the two points see opposite seasons and roughly opposite clock times.

Why almost everyone's other side is water

About 86 per cent of the surface is ocean and land clusters in the north, so the antipode of a random land point is almost always sea. The rare land-on-land pairs are a standing curiosity: much of the Americas sits opposite the Indian Ocean and east Asia, which is why Santo Domingo in Dominican Republic resolves to Yogyakarta, and the antipode itself is water. The nearest place quoted here is the closest of the 341 positions this site carries coordinates for — a useful, honest bound rather than a claim about every village on Earth.

Try any position

The form accepts any latitude and longitude and returns the antipode in decimal and degrees-minutes-seconds, the surface arc and the through-Earth diameter, all from the two lines of arithmetic above. It runs on your device: no request leaves the page, so an edit is answered instantly and offline, and the same maths works for a hill you were standing on as for a capital city. Flight planners use the figure for the longest sectors on the board, and geography teachers use it for the question above.

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