What Is Latitude and Longitude?

Latitude and longitude are a pair of angles that describe where a point sits on the surface of the Earth. Latitude says how far north or south of the equator a place is, and longitude says how far east or west it is from a reference line called the prime meridian. Together they give a unique address for any spot on the planet, with no street names or languages involved.

Latitude: north and south

Lines of latitude are imaginary circles that run east to west around the globe. The equator is the line at 0 degrees. The North Pole is at 90 degrees north and the South Pole at 90 degrees south, so latitude always falls between -90 and 90.

These circles are also called parallels because they never meet. Moving one degree of latitude north or south covers a similar distance anywhere on Earth, which is why latitude is the easier of the two measures to reason about. You can read more in our guide to how long a degree of latitude and longitude is.

Longitude: east and west

Lines of longitude, or meridians, run from pole to pole. The prime meridian, set at 0 degrees, passes through Greenwich in London. Longitude is measured east or west of it, up to 180 degrees in each direction, and the 180 degree line sits roughly in the middle of the Pacific Ocean.

Unlike parallels, meridians all converge at the poles. That means the ground distance covered by one degree of longitude is widest at the equator and shrinks to nothing at the poles.

Writing coordinates

A coordinate pair is normally written latitude first, then longitude. There are several notations:

• Decimal degrees: 40.7128, -74.0060
• With hemisphere letters: 40.7128 N, 74.0060 W
• Degrees, minutes and seconds: 40 degrees 42 minutes 46 seconds N

The first two mean the same thing. See decimal degrees vs degrees, minutes and seconds for how the formats compare, and positive and negative coordinates for what the minus sign means.

Why it matters

Almost every digital map, navigation app and delivery system stores positions as latitude and longitude. They are language-neutral, consistent worldwide and precise enough for a single doorway when written with enough decimals. The decimal places guide shows how many digits you need for different levels of detail.

Coordinates are not very friendly to remember or read aloud, though. That is why short location codes exist: a system such as UPCS turns a latitude and longitude into a compact code that stands for a 3 m by 3 m cell, so that the exact spot can be shared easily next to a normal address.