EPSG / CRS Code Finder & PROJ4 Explorer
What are EPSG Codes?
EPSG codes (named after the now-defunct European Petroleum Survey Group) are unique numeric identifiers for coordinate reference systems (CRS) used worldwide. When you set a projection in QGIS, PostGIS, or any GIS software, you are selecting an EPSG code.
Common examples: EPSG:4326 (WGS84 latitude/longitude), EPSG:3857 (Web Mercator for Google/Bing/OSM tiles), EPSG:6668 (JGD2011 geographic for Japan), EPSG:32633 (UTM Zone 33N).
EPSG / CRS Quick Explorer
Search by EPSG code number, name, or region. Results include the PROJ4 definition string, usage bounds, and datum information.
How to Find the Right EPSG Code for Your Project
- Determine your region and whether you need a geographic (lat/lon degrees) or projected (meters/feet) CRS.
- For web map tiles (Google, Bing, OpenStreetMap), use EPSG:3857 (Web Mercator).
- For GPS raw data storage and GeoJSON, use EPSG:4326 (WGS84).
- For surveying in Japan with meter-based grid coordinates, use JGD2011 Plane Rectangular zones (e.g., EPSG:6677 for Tokyo, Zone IX).
- For UTM coordinates, find your zone number (e.g., Zone 54N for eastern Japan) and look up EPSG:326xx.
FAQ
Q: What is the difference between EPSG:4326 and EPSG:3857?
EPSG:4326 is WGS84 geographic coordinates (latitude/longitude in degrees). EPSG:3857 is Web Mercator, a projected system that converts those degrees into flat X/Y meters for tile-based web maps. They represent the same locations but in different mathematical spaces.
Q: Can I use EPSG:4326 for area calculations?
No. EPSG:4326 uses angular degrees, which distort area measurements. Project your data into a local metric CRS (UTM or State Plane) before computing areas or distances.