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NGR Help

Find your National Grid Reference (NGR)

SEPA have developed a web based NGR tool using online maps to help determine a National Grid Reference. By entering your postcode a map of your area will displayed. By clicking on the map a 10 character National Grid Reference will be displayed for your use.


Reading a National Grid Reference (NGR)

The British National Grid System divides the United Kingdom into a grid of 100km squares and each square has a pair of identifying letters. This grid appears on all OS Landranger and Pathfinder maps.

To read your National Grid Reference (NGR)

  1. Find your location on a suitable map.
  2. Identify the corresponding letter pair for the location (see diagram opposite)
  3. On your map, measure the Easting coordinate
    The distance from the left-hand edge of the square on the map.
  4. On your map measure the Northing coordinate.The distance from the bottom edge of the square on the map.
  5. NGR = (Letter pair) + (Easting) + (Northing)
Os Grid V Variation 1



  • In this example, our location is shown on an OS Landranger map.
  • The location lies within NS square on the national grid (indicated in the diagram above).
  • The Easting (X) map coordinate is 4227.
  • The Northing (Y) map coordinate is 8364.
  • The NGR for this location is: NS42278364