GPS Coordinates Converter

Paste a coordinate in any common format — decimal pair (40.7128, -74.0060), DMS (40°42'46"N 74°00'21"W), or DMM (40°42.766'N 74°00.35'W) — and see all three side by side. Also produces a geo: URI for mobile mapping apps and a Google Maps link you can open directly. Hemisphere markers (N/S/E/W) are inferred from sign for decimal inputs and respected for DMS/DMM.

The three formats say the same thing in different bases, and mixing them up is the most common way a coordinate ends up in the wrong hemisphere or the wrong ocean. Decimal degrees divide the fraction by ten; DMS divides it by sixty twice; DMM stops after one division and keeps the rest as a decimal minute, which is the form marine and aviation charts use. Reading 40°42.766' as 40.42766 rather than 40.71277 puts you roughly thirty kilometres away and still looks like a plausible coordinate.

The sign and the hemisphere letter carry the same information, so a value should have one or the other and not both. A negative longitude with a W is contradictory, and different tools resolve it differently — some take the letter, some take the sign, some multiply the two and give you the eastern hemisphere. Latitude comes first in every convention here, which is also the order of a geo: URI; GeoJSON is the exception, listing longitude first.

Decimal places are a claim about precision. The fourth is about eleven metres at the equator, the sixth about eleven centimetres, and anything beyond the seventh is noise no consumer receiver can support. Copying a nine-decimal figure out of a database does not make the position more accurate; it makes the error invisible.

All of this assumes WGS 84, the datum used by GPS and by every web map. National grid systems and older local datums can name the same point with coordinates that differ by tens or hundreds of metres, and converting between them needs a transformation this tool does not do.