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Coordinate Formats Explained: Decimal, DMS, UTM and MGRS

Paste a coordinate in any common format, or use your location, and read it in all the others. Below, how each format works.

Updated 1 October 2026

Accepts decimal (48.8584, 2.2945), degrees-minutes (48 51.5 N 2 17.67 E) and DMS (48°51′30″N 2°17′40″E). Everything runs in your browser; nothing is sent anywhere. All formats here are on the WGS 84 datum used by GPS.

Latitude and longitude

Latitude is the angle north or south of the equator, from 0° to 90°. Longitude is the angle east or west of the prime meridian at Greenwich, from 0° to 180°. The same position can be written three ways:

Format	Example	Used by
Decimal degrees (DD)	48.858370, 2.294481	Phones, web maps, GPX files, most software. South and west are negative.
Degrees, decimal minutes (DDM)	48° 51.5022′ N, 2° 17.6689′ E	Marine chartplotters, aviation, geocaching.
Degrees, minutes, seconds (DMS)	48° 51′ 30.13″ N, 2° 17′ 40.13″ E	Paper maps, surveys, legal descriptions.

A degree has 60 minutes and a minute has 60 seconds, so DD = degrees + minutes/60 + seconds/3600.

How precise is each digit?

One degree of latitude is about 111 km everywhere. A degree of longitude is 111 km at the equator and shrinks toward the poles (about 73 km at 49° N). For latitude:

Decimal places	Roughly	Enough for
2 (0.01°)	1.1 km	A town
3 (0.001°)	110 m	A neighbourhood
4 (0.0001°)	11 m	A building, a parking spot
5 (0.00001°)	1.1 m	The limit of what a phone GPS can resolve
6 (0.000001°)	11 cm	Survey work; beyond phone accuracy

A phone in open sky is typically accurate to a few metres, so five decimal places carry all the real information. More digits are not more accurate. See how accurate is phone GPS?

UTM: metres on a grid

Universal Transverse Mercator divides the world between 80° S and 84° N into 60 zones, each 6° of longitude wide, numbered eastward from 180°. Inside each zone a position is given as an easting and a northing in metres, on a flat grid. The zone's central meridian is given an easting of 500,000 m so no value is negative. Northing is metres from the equator, and in the southern hemisphere 10,000,000 m is added. A letter after the zone number marks the 8° latitude band.

The appeal is that distances are simple: two points 1,000 m apart in easting are 1 km apart. That is why hikers, search and rescue teams and surveyors like it with a paper map that has a UTM grid. Two exceptions to the regular zones: zone 32V is widened to cover south-western Norway, and zones 31X to 37X are rearranged around Svalbard. The poles use a different grid, UPS.

MGRS: UTM in a shorter form

The Military Grid Reference System, used by NATO forces and many emergency services, is built on UTM. It adds a two-letter code for each 100 km square, so the long easting and northing shrink to the digits inside that square. In 31U DQ 48250 11951, 31U is the zone and band, DQ the 100 km square, and the two five-digit numbers the easting and northing in metres within it. Dropping digits from the end of each number gives a coarser reference: 4+4 digits is a 10 m square, 3+3 is 100 m.

Datums: why the same numbers can point to different places

A coordinate only means something with its datum, the model of the Earth's shape it is measured on. GPS uses WGS 84. Older national maps use local datums such as NAD27 in North America or OSGB36 in Britain, and the same numbers on a different datum can be tens to hundreds of metres apart. If coordinates from an old map do not match your phone, the datum is the first thing to check.

Sources

J. P. Snyder, Map Projections: A Working Manual, USGS Professional Paper 1395 (1987): the transverse Mercator formulas used above.
USGS, The Universal Transverse Mercator (UTM) grid, Fact Sheet 077-01.
NGA, The Universal Grids and the Transverse Mercator and Polar Stereographic Map Projections (NGA.SIG.0012), as implemented in GeographicLib (the Norway and Svalbard zone exceptions).
USGS, How much distance does a degree, minute and second cover on your maps?