Lambert 93 to OSGB36 National Grid Coordinate Converter
Free online tool to convert coordinates from RGF93 / Lambert-93 (France mainland) (EPSG:2154) to OSGB36 / British National Grid (EPSG:27700). Professional-grade accuracy using proj4, zero install, runs in your browser.
About Lambert 93
RGF93 / Lambert-93 (France mainland) (EPSG:2154). The official projection of metropolitan France since 2000. Covers all mainland France + Corsica in a single system with minimal distortion.
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 Lambert 93 and OSGB36 National Grid?
Lambert 93 (EPSG:2154) is national grid and based in France, while OSGB36 National Grid (EPSG:27700) is national grid based in UK. The official projection of metropolitan France since 2000. Covers all mainland France + Corsica in a single system with minimal distortion. 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 Lambert 93, 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:2154&to=EPSG:27700&coords=lat,lng for programmatic access. It returns the transformed coordinates as JSON.