Coordinate Converter — DMS, Decimal, UTM, MGRS

One converter for every coordinate format

Latitude and longitude can be written in many ways. Web maps and GPS apps use decimal degrees such as 40.7128, -74.0060. Older maps, nautical charts and aviation documents use degrees, minutes and seconds (DMS), for example 40° 42′ 46″ N. Marine and handheld GPS units often show degrees and decimal minutes (DDM), like 40° 42.768′ N. Surveyors and the military work in metres on a grid instead: UTM splits the world into 60 zones of 6° width, and MGRS builds on UTM with 100 km grid-square letters and an even number of digits for the position inside the square. Web maps also use Web Mercator (EPSG:3857), a projected system in metres used by most tile-based map services.

This tool reads all of them. Paste one coordinate per line; it detects the format automatically, accepts hemisphere letters before or after the numbers, degree, minute and second symbols or plain spaces, and even decimal commas. Every line is converted to the format you choose, or to a table showing all formats at once. Invalid lines are listed with a clear message instead of stopping the whole batch.

How the conversions work

Conversions between degrees formats are exact arithmetic: one degree is 60 minutes and one minute is 60 seconds. UTM uses the transverse Mercator projection on the WGS 84 ellipsoid with a scale factor of 0.9996 on the central meridian, a false easting of 500,000 m and, in the southern hemisphere, a false northing of 10,000,000 m. The implementation uses the Krüger series, accurate to well below a millimetre inside a zone, and includes the special zones for Norway and Svalbard. Web Mercator is computed with the proj4 library, loaded only when needed.

Precision matters: six decimal places of a degree correspond to roughly 11 centimetres, four decimals to about 11 metres. Use more digits when you need survey-level accuracy, and fewer for a readable label. Because this is a pure coordinate conversion and not a datum transformation, results assume WGS 84 input and output.

Tips for reliable results

Always check the order: most tools write latitude first, while GeoJSON and many GIS files store longitude first. If a value is out of range, such as a latitude above 90°, the converter tells you rather than guessing. Keep hemisphere signs consistent: negative latitude is south, negative longitude is west. Everything is processed locally, so you can safely convert sensitive site locations or survey data.