Convert British National Grid (BNG; formerly known as the National Grid Reference (NGR)) to latitude and longitude (lat/long WGS84) or vice versa.
See The Ordnance Survey’s guide to grid references for an explanation of how the BNG works.
This coordinate converter uses the Oracle Spatial 10g coordinate transformations using approved (recommended) EPSG codes for BNG, WGS84 and ETRS89, which are 27700, 4326 and 4258 respectively. Technical details can be provided on request.
Due to popular demand, we have now published a guide for bulk conversion of coordinates.