How this instrument works
An antipodal point, or antipode, is the location diametrically opposite another point on Earth's surface — the two points sit at opposite ends of a straight line drawn through the planet's centre. If you could tunnel straight down from any spot and keep going, the antipode is where you would, in principle, come out the other side.
The math is simple because a sphere makes it simple: flip the sign of the latitude, since a point at 40° North becomes 40° South and vice versa, and shift the longitude by exactly 180°, wrapping around so the result stays within the standard -180° to 180° range. A longitude greater than zero subtracts 180; a longitude at or below zero adds 180 — either way the result lands on the meridian exactly opposite the original.
Antipodes are a popular piece of geography trivia precisely because they're so often disappointing: about 71% of Earth's surface is ocean, and roughly 15% of land area has another patch of land at its antipode, so most populated places — New York, Sydney, London — turn out to have watery opposites. The Southern Hemisphere's relative scarcity of land makes this lopsided further still.
- Enter Latitude in degrees, using positive values for North and negative for South.
- Enter Longitude in degrees, using positive values for East and negative for West.
- Read Antipode latitude and Antipode longitude — the coordinates of the diametrically opposite point.
- Latitude must stay between -90 and 90 and longitude between -180 and 180; the instrument flags anything outside that range.
- Try the default New York City coordinates first, then swap in your own city to see how often the antipode lands in open ocean.
Worked example — New York City's antipode
Enter Latitude 40.7128 and Longitude -74.006, New York City's coordinates. Antipode latitude is simply the sign flip: -40.7128. Longitude is negative, so the instrument adds 180: -74.006 + 180 = 105.994. Antipode latitude reads -40.7128 and Antipode longitude reads 105.994.
That point sits in the southern Indian Ocean, well southwest of Australia — a widely cited piece of trivia, since it means New York's exact opposite point on the globe is empty water, thousands of kilometres from the nearest shore.
Questions
What exactly is an antipode?
It's the point on Earth's surface diametrically opposite another point — the two locations sit at either end of a straight line through the planet's centre. Flying or tunnelling from one to the other in a straight line covers Earth's full diameter, about 12,742 km, the longest possible straight-line distance between two surface points.
Why does my antipode almost always land in the ocean?
Because so much of Earth is ocean. Roughly 71% of the planet's surface is water, and only about 15% of land area has its antipode on land as well — the rest of land's antipodes fall on water. The Southern Hemisphere has comparatively little land, so land in the Northern Hemisphere is especially likely to have an oceanic opposite, which is exactly why cities like New York and London land on empty ocean.
Why does the longitude formula add or subtract 180 depending on the sign?
Longitude is measured from -180° to 180°, so the ±180° shift has to wrap around to stay inside that range. Adding 180 to a longitude already above 0 would push it past 180, so the instrument subtracts instead; the reverse holds for negative or zero longitudes. Either operation moves the point exactly halfway around the globe — the sign choice is only about keeping the result in the standard range.
Are there any places where both a location and its antipode are on land?
Yes, though they're the exception rather than the rule. Well-known pairs include parts of Spain and New Zealand's North Island, and parts of Chile and eastern China/Mongolia. These land-to-land pairs cover only a small fraction of Earth's land area, which is what makes them noteworthy enough to be listed as trivia in the first place.
What happens if I enter a latitude or longitude outside the valid range?
The instrument flags it. Latitude must stay between -90° and 90° (the poles), and longitude between -180° and 180°; values outside those bounds don't correspond to a real point on Earth, so the instrument asks for a corrected entry before computing an antipode.
Is 'antipode' the same as 'the other side of the world' in casual speech?
Usually yes, but casual usage is looser than the geographic definition. People often say 'the other side of the world' about anywhere far away, while an antipode specifically means the one exact point diametrically opposite — every location has exactly one true antipode, not a whole distant region.