A geohash is a short string that names a rectangle on the Earth; more characters, a smaller rectangle. Encode a point, decode a hash, and see the cell and its neighbours on the map.
How to use it
Paste coordinates or a geohash, or click the map, or use your location.
Set the precision with the slider: more characters, a smaller cell.
Read the geohash, the cell bounds and the eight neighbours. Click a neighbour to move to it.
5 practical uses
Make a short code for a place to share in a message or a spreadsheet.
Understand the geohash a database or an API gives back.
Choose the precision for indexing or clustering points.
See which neighbouring cells a search near a boundary must include.
Decode a geohash found in a log or a URL.
The maths behind it
A geohash interleaves the bits of two binary searches: at each step the longitude range (or, alternately, the latitude range) is halved and a bit records which half holds the point. Every five bits become one character of the base-32 alphabet. A hash of n characters has 5n bits, about 2.5n for each axis, so each extra character makes the cell about 32 times smaller in area.
A short string that names a rectangle on the Earth. The world is halved again and again, alternating longitude and latitude, and the choices are written five bits to a character.
How precise is a geohash?
Five characters is about 5 km; seven about 150 m; nine about 5 m; twelve a few centimetres.
Why are the letters a, i, l and o missing?
The geohash alphabet uses 32 symbols, the digits and the letters without a, i, l and o, to avoid confusion when read aloud.
Embed this tool on your website
Paste this code where the tool should appear. It shows the tool alone, without this page's text, and links back here. It is free to use; the map data credit stays on the map.
Change height to suit your page. To open the tool with a place already set, add the settings from this page's address bar (the part after #) to the end of the src. The embedded tool asks the visitor's browser for their location only when they press the button, and the allow attribute lets that work inside the frame.