Coordinate Converter
Convert coordinates between any two coordinate reference systems. Supports all EPSG codes — WGS84, UTM, State Plane, NAD83, and more.
Convert coordinate notation
About the Coordinate Converter
This tool converts a coordinate pair from one coordinate reference system (CRS) to another using the proj4js library. It supports all 8,000+ EPSG codes defined by the IOGP.
What is an EPSG code?
EPSG codes are standardized numeric identifiers for coordinate reference systems maintained by the International Association of Oil & Gas Producers (IOGP). For example, EPSG:4326 refers to WGS 84 (the GPS coordinate system), while EPSG:3857 is the Web Mercator projection used by Google Maps, OpenStreetMap, and other web mapping platforms.
When do you need coordinate conversion?
- Combining datasets that use different projections (e.g. UTM zones with lat/lon data)
- Importing GPS coordinates (WGS 84) into a local state plane system
- Verifying coordinate values between software like ArcGIS, QGIS, or PostGIS
- Debugging projection issues in web mapping applications
DMS vs. Decimal Degrees — What's the Difference?
Geographic coordinates can be expressed in three common notations, all representing the same location:
- Decimal Degrees (DD):
40.714269°— used by most GIS software, databases, and web APIs. Simplest for computation. - Degrees Minutes Seconds (DMS):
40° 42' 51.37" N— traditional format used on topographic maps, in surveying, and by many GPS devices. - Degrees Decimal Minutes (DDM):
40° 42.856' N— common in marine navigation, aviation, and handheld GPS receivers.
Converting between these notations is not the same as converting between coordinate reference systems. Notation conversion changes how the number is displayed; CRS conversion changes the actual coordinate values by applying a mathematical projection.