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Coordinates

National grid converter

Convert coordinates between latitude and longitude, UTM and the official grids of the UK, Ireland, France, Germany, Switzerland, the Netherlands, Portugal and Spain. Every conversion tells you how accurate it really is.

Accuracy: about 2 m · EPSG:1314

Example two landmarks to British National Grid. Paste your own or tap the map.

Loading the map…

Tap the map to add that spot in the “From” system. Points on the map are shown in WGS84.

The systems and how accurate each one is

Getting from latitude and longitude to a national grid takes two steps. The projection (the math that turns degrees into meters on a flat grid) is exact to the millimeter for every system here. The datum change is where the error comes in: some grids sit on ETRS89, which matches GPS to well under a meter, and others sit on older national datums that need a shift.

National grids in this converter, with their datum change and accuracy
SystemWhereDatum changeAccuracy
British National Grid (EPSG:27700)Great Britain7-parameter Helmert, OSGB36 (EPSG:1314)about 2 m
Irish Transverse Mercator (EPSG:2157)Ireland and Northern IrelandNone: it’s on ETRS89exact
Lambert-93 (EPSG:2154)Mainland France and CorsicaNone: RGF93 is ETRS89exact
Gauss-Krüger zones 2–5 (EPSG:31466–31469)Germany (older data)BeTA2007 national grid (EPSG:15948)about 1 m
LV95 (EPSG:2056)Switzerland and Liechtenstein3-parameter shift, CH1903+ (EPSG:1647)about 0.1 m
RD New (EPSG:28992)Netherlands7-parameter Helmert, Amersfoort (EPSG:4833)about 1 m
PT-TM06 (EPSG:3763)Mainland PortugalNone: it’s on ETRS89exact
ED50 / UTM 29–31 (EPSG:23029–23031)Spain (pre-2015 maps)IGN SPED2ETV2 grid (EPSG:15932)about 0.2 m
UTM (WGS84)WorldwideNoneexact

“Exact” means exact with respect to ETRS89. GPS and Google Maps work in WGS84, which in Europe today differs from ETRS89 by a little under 1 m. That only matters for survey work.

When you need more than this

For the British National Grid, Ordnance Survey’s OSTN15 transformation gets to a few centimeters, compared with about 2 m for the Helmert shift used here. For the Netherlands, RDNAPTRANS2018 is the official centimeter-level method. Both are available in GIS software such as QGIS. For mapping, navigation, hiking, real estate or checking where a point is, the accuracy here is plenty; for setting out a building or a boundary, use the official tools or a surveyor.

Germany and Spain are special cases: there, the converter uses the official national grid files (BeTA2007 and the Spanish IGN’s SPED2ETV2), the same ones PROJ, QGIS and ArcGIS use, interpolated in your browser.

Tips for each country

  • United Kingdom. You can paste OS grid references with letters (“TQ 302 796” or “TQ 30268 79643”) as well as plain eastings and northings, and the results show both.
  • Germany. The first digit of a Gauss-Krüger easting (Rechtswert) is the zone: 4 593 627 is zone 4, centered on 12° E. Today’s official system is ETRS89/UTM zones 32 and 33, which you get with “UTM (WGS84).”
  • Switzerland. LV95 eastings start with 2 and northings with 1 (2 600 000 / 1 200 000 is the old observatory in Bern). The older LV03 drops those leading digits: adding 2 000 000 and 1 000 000 gets you close, but not exactly, because the official conversion also corrects distortions in the old network.
  • France. Lambert-93 eastings are around 100 000 to 1 200 000 and northings 6 000 000 to 7 200 000. The old Lambert II étendu (NTF) isn’t supported.
  • Spain. Use the zone your data was produced in, even if the point falls in the next one; ED50 coordinates are about 230 m away from today’s.

Frequently asked questions

How do I convert latitude and longitude to British National Grid?

Choose “Latitude and longitude” in From and “British National Grid” in To, then paste your coordinates, one pair per line. You’ll get the easting and northing and the OS grid reference, within about 2 m.

Why does each system have a different accuracy?

Because the datums differ. Grids built on ETRS89 (Irish ITM, Lambert-93, PT-TM06) match GPS directly. Older ones (OSGB36, DHDN, Amersfoort, ED50) need a shift whose accuracy is set by the official transformation, and that’s the figure shown.

Which Gauss-Krüger zone should I use?

The one your data was made in, which is the first digit of the easting. For a new point, the zone is the longitude divided by 3, rounded: 2 (6° E), 3 (9° E), 4 (12° E) or 5 (15° E).

Can I convert a whole list?

Yes, up to 100 points at once. Paste one per line, optionally with a name first, then copy the table into your spreadsheet or download it as a CSV.

Does it work for the US State Plane system?

Not at the moment. For US coordinates, use “UTM (WGS84)” here or the coordinate converter, which also gives MGRS.

Do my coordinates leave my computer?

No. All the math, including the German and Spanish grid files, runs in your browser. Only the map tiles and the grid files themselves are downloaded.

Related tools

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Latitude and longitude finder Search for any place or address, or tap the map, and copy its latitude and longitude in one click. Plot coordinates on a map Paste a latitude and longitude in any format and see the exact spot on the map, ready to share. Coordinate converter Convert coordinates between decimal degrees, DMS, UTM, MGRS, geohash and Plus Codes in one go. UTM to latitude and longitude Turn a UTM zone, easting and northing into latitude and longitude, and see the point on the map.

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