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Coordinate transformation tool

Please select the coordinates you wish to transform. If you have a whole batch of coordinates to transform visit our batch transformation page. Please note this transformation only operates within Great Britain and up to 10km offshore.


Degrees, Minutes, Seconds

*Denotes a required field.

Degrees, Decimal Minutes

*Denotes a required field.

Decimal Degrees

*Denotes a required field.


*Denotes a required field.

OSGB36 National Grid

Eastings and Northings

*Denotes a required field.

The Coordinate Transformation Tool transforms GPS based ETRS89 latitude and longitude or cartesian XYZ coordinates to the equivalent OSGB36 National Grid eastings and northings, and vice-versa, using Ordnance Survey's National Grid Transformation OSTN02. It also transforms GPS ellipsoid heights to orthometric (mean sea level) heights on the relevant Ordnance Survey mapping datum (Ordnance Datum Newlyn for mainland Britain), using the National Geoid Model OSGM02.

To read an article about the development of the OSTN02 transformation see the November/December 2001 edition of Geomatics World Magazine.

To read a report about the development of the OSGM02 Geoid Model.

A spreadsheet that includes many projection coordinate functions, including functions to re-format coordinates into the Degrees, Minutes, Seconds format.

For more information about OSTN02 and OSGM02

For general information on coordinate systems and conversions

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