How geohash works
A geohash encodes latitude and longitude as letters and digits by repeatedly halving the longitude and latitude ranges. Each extra character divides the cell by 32: 5 characters is about 5 km, 7 about 150 m and 9 about 5 m. Databases use it to find nearby points quickly.
Frequently asked questions
Do nearby points always share a geohash prefix?
Usually, but points on either side of a cell boundary can have very different codes, so proximity searches also look at neighbouring cells.
More tools
Coordinate converterAny format to all the others, with a map. UTM zone finderZone, band and central meridian of any point. Batch coordinate converterA whole spreadsheet at once, with KML and GPX. Distance between two coordinatesDistance, bearing and midpoint on the ellipsoid. Area from coordinatesArea in acres and hectares from the corners. Sunrise, sunset and twilightSunrise, sunset, twilight and a monthly daylight table. Hiking time calculatorWalking time from distance, elevation gain and a GPX track.