A coordinate converter translates a single point on Earth between the notations used by maps, surveys, and GPS devices. Decimal degrees are easy for computers, degrees-minutes-seconds (DMS) appear on nautical charts, and UTM grids and Geohashes are handy for engineering and databases. This free tool shows all of them at once, using standard WGS84 formulas entirely in your browser.
Which format do you need?
Different tools and professions expect different coordinate notations. Here is a quick guide to choosing the right one:
| Format | Looks like | Best for |
|---|---|---|
| Decimal degrees (DD) | 51.5074, -0.1278 | APIs, databases, most web maps (Google Maps, OpenStreetMap) |
| Degrees-minutes-seconds (DMS) | 51°30’26.6”N 0°7’40.1”W | Printed nautical and aeronautical charts, GPS units |
| Degrees-decimal minutes (DDM) | 51°30.444’N 0°7.668’W | Marine GPS receivers, some aviation software |
| UTM | 30U 699334 5710062 | Engineering surveys, military maps, GIS projects |
| Geohash | gcpvj | Proximity search in databases, location caching, spatial indexing |
How it works
Decimal degrees ↔ DMS/DDM. A signed decimal degree is split into whole degrees, whole minutes, and seconds. The sign becomes a hemisphere letter: N/S for latitude, E/W for longitude. DDM keeps minutes as a decimal instead of breaking out seconds.
UTM. The globe is divided into 60 zones, each 6° of longitude wide. Latitude and longitude are projected onto a transverse Mercator using a truncated series expansion of the WGS84 ellipsoid, producing an easting (metres from the zone’s false origin) and a northing (metres from the equator, with a 10,000,000 m offset south of the equator). The result is reported as zone hemisphere easting northing.
Geohash. The tool interleaves bits from a binary search of the latitude range (−90…90) and longitude range (−180…180), then base-32 encodes five bits per character. Longer strings carry more bits and therefore more precision.
Example and tips
The point 40.17719, 44.51453 (near Yerevan, Armenia) converts to roughly:
DMS: 40°10'37.9"N 44°30'52.3"E
DDM: 40°10.632'N 44°30.872'E
UTM: 38T 458930 4447190
Geohash: szx7s...And for London (51.5074, -0.1278):
DMS: 51°30'26.6"N 0°7'40.1"W
UTM: 30U 699334 5710062
Geohash: gcpvj...Understanding Geohash precision
Geohash length determines precision. Shorter strings cover larger areas and are useful for grouping nearby results; longer strings pinpoint a location:
| Characters | Approximate area covered |
|---|---|
| 4 | ~40 km × 20 km |
| 6 | ~1.2 km × 0.6 km |
| 8 | ~38 m × 19 m |
| 9 | ~5 m × 5 m |
| 11 | ~3 cm × 3 cm |
A common database pattern is to store a 6-character Geohash and index it — then a proximity query becomes a prefix search, which is fast on any standard index.
Notes on datum and accuracy
- Always confirm your source data is WGS84 before trusting metre-level results.
- Geohash length controls precision — trim characters for coarser areas, add them for pinpoint locations.
- UTM eastings are kept inside a single zone; a point near a zone edge will still convert but neighbouring features may sit in a different zone.
- Older survey data may use national datums (OSGB36 in Great Britain, NAD27 in North America) that can be offset from WGS84 by tens of metres. This tool does not convert between datums.