ETRS89 UTM 30N to OSGB36 National Grid Coordinate Converter
Free online tool to convert coordinates from ETRS89 / UTM zone 30N (Spain west) (EPSG:25830) to OSGB36 / British National Grid (EPSG:27700). Professional-grade accuracy using proj4, zero install, runs in your browser.
About ETRS89 UTM 30N
ETRS89 / UTM zone 30N (Spain west) (EPSG:25830). Spanish official system for western regions (Galicia, Asturias, Extremadura, western Portugal). ETRS89 datum, EU standard.
About OSGB36 National Grid
OSGB36 / British National Grid (EPSG:27700). Ordnance Survey Great Britain 1936 datum — the national grid system for England, Scotland and Wales. Universally used in UK survey and cadastre.
Frequently Asked Questions
What is the difference between ETRS89 UTM 30N and OSGB36 National Grid?
ETRS89 UTM 30N (EPSG:25830) is utm and based in Spain, while OSGB36 National Grid (EPSG:27700) is national grid based in UK. Spanish official system for western regions (Galicia, Asturias, Extremadura, western Portugal). ETRS89 datum, EU standard. In contrast, ordnance survey great britain 1936 datum — the national grid system for england, scotland and wales. universally used in uk survey and cadastre.
Is this conversion accurate for surveying?
Yes. The conversion uses the industry-standard proj4 library with full datum shift parameters (). Typical accuracy is sub-meter for civilian applications. For cadastral precision, always verify against the official agency datum.
What coordinate format should I use?
For ETRS89 UTM 30N, enter coordinates as easting, northing in meters (e.g. 514500, 5033880). The tool auto-detects the format.
Can I convert many points at once?
Yes, use our batch CSV converter. Upload a CSV with your points, select the transformation, download the converted file. Free with a SurveyingPedia account.
Is there an API?
Yes — call /api/v1/transform?from=EPSG:25830&to=EPSG:27700&coords=lat,lng for programmatic access. It returns the transformed coordinates as JSON.