Convert OSGB36 to ED50

Convert coordinates from OSGB36 (EPSG:4277) to ED50 (EPSG:4230) — official EPSG transformation parameters, accuracy and area of use, with a free in-browser converter.

From

Input (lon, lat (decimal degrees))

Output (lon, lat (decimal degrees))

Direct link to this transformation: epsgtransform.com/transform/epsg-4277-to-epsg-4230

Official EPSG transformation from OSGB36 to ED50

The EPSG Geodetic Parameter Dataset defines 1 transformation between OSGB36 (EPSG:4277) and ED50 (EPSG:4230). Its parameters, accuracy and area of use are listed below.

OSGB36 to ED50 (1)

EPSG:1315±2 m

Method:: Position Vector transformation (geog2D domain)
Area of use:: UK - Great Britain onshore and nearshore; Isle of Man
Scope:: Oil and gas exploration and production.

Parameter	Value	Unit
X-axis translation(tx)	535.948	metre
Y-axis translation(ty)	-31.357	metre
Z-axis translation(tz)	665.16	metre
X-axis rotation(rx)	0.15	arc-second
Y-axis rotation(ry)	0.247	arc-second
Z-axis rotation(rz)	0.998	arc-second
Scale difference(ds)	-21.689	parts per million

Known as the "UKOOA landward/seaward transformation". This transformation is concatenated from OSGB36 to WGS 84 (6) (Petroleum) (code 1314) minus ED50 to WGS 84 (18) (Common Offshore) (code 1311). Accuracy better than 4m and generally better than 2m.

Convert EPSG:4277 to EPSG:4230 in code

The same transformation with common GIS tools and libraries:

from pyproj import Transformer

transformer = Transformer.from_crs("EPSG:4277", "EPSG:4230", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)

Source: EPSG:4277 — OSGB36

geographic system using latitude and longitude on an ellipsoid · Area of use: UK - Britain and UKCS 49°45'N to 61°N, 9°W to 2°E

+proj=longlat +ellps=airy +no_defs +type=crs

More about EPSG:4277 →

Target: EPSG:4230 — ED50

geographic system using latitude and longitude on an ellipsoid · Area of use: Europe - ED50 by country

+proj=longlat +ellps=intl +no_defs +type=crs

More about EPSG:4230 →

Frequently asked questions

How accurate is converting OSGB36 to ED50?: The most accurate official EPSG transformation between these systems is accurate to about ±2 m within its stated area of use. Browser-based converters approximate datum shifts with Helmert parameters; for surveying-grade work apply the official transformation in a desktop GIS.
Does my data leave the browser when I use this converter?: No. All coordinate transformations are computed locally in your browser using proj4js. The coordinates you enter are never transmitted to any server.

Need the reverse? Convert EPSG:4230 to EPSG:4277 →