Coordinate converter

The formats, one by one

Here’s the same spot, the Empire State Building in New York, written the seven ways this converter understands. You can paste any of them into the box above.

A Google Maps, Apple Maps or OpenStreetMap link works too: the converter pulls the coordinates out of the link. Google’s short share links (maps.app.goo.gl) don’t include them, so open the link first and copy the long address from your browser.

How UTM and MGRS work

UTM splits the Earth into 60 zones, each 6° of longitude wide, numbered 1 to 60 eastward from the 180th meridian. Each zone is drawn on a flat grid in meters. The easting is the distance east, with 500,000 m at the zone’s central meridian, and the northing is the distance from the equator. South of the equator, northings start at 10,000,000 m so they never go negative.

The letter after the zone number, like the T in “18T,” is the latitude band: 8° strips from C (80° S) to X (84° N). You don’t need it to locate the point if you know the hemisphere, but it helps catch mistakes. Watch out for N and S: some apps use them for the hemisphere rather than the band, so the converter checks the northing to tell which one you meant.

MGRS is UTM with the zone split into 100 km squares named by two letters, so “18T WL 85631 11326” is easting 585,631 and northing 4,511,326 in zone 18T (MGRS cuts off the digits rather than rounding them). Five digits per axis is 1 m, four is 10 m, three is 100 m. The contiguous United States spans zones 10 (the West Coast) through 19 (Maine).

WGS84, NAD83 and NAD27

GPS units, phones and Google Maps use WGS84. US surveying and state data mostly use NAD83, which today is within about 1 to 2 m of WGS84, close enough for finding a place or plotting a trail. Older USGS topo maps and many pre-1990s records use NAD27, which can be off by tens of meters, up to about 100 m. If coordinates from an old map land slightly off, that’s usually why.

Common mistakes

• Latitude and longitude swapped. Latitude comes first. In the contiguous US, latitude runs from about 24 to 49 and longitude from about −67 to −125. If both numbers fit either way, the converter can’t tell, so check that the pin lands where you expect.
• The missing minus sign. Everything in the Americas is west of Greenwich, so longitude is negative (or ends in W). Without the minus, New York ends up in Kyrgyzstan.
• Decimal minutes aren’t seconds. 40°44.5′ is 40°44′30″, not 40°44′50″.
• Wrong UTM zone. The same easting and northing in the next zone over lands about 500 km away. If the point is way off, check the zone.
• Mixing up datums. If two maps disagree by tens of meters, one of them is probably on NAD27.