NAD27 to NAD83 (lat/lng) Coordinate Converter
Free online tool to convert coordinates from North American Datum 1927 (EPSG:4267) to North American Datum 1983 (EPSG:4269). Professional-grade accuracy using proj4, zero install, runs in your browser.
About NAD27
North American Datum 1927 (EPSG:4267). Legacy US datum (Clarke 1866 ellipsoid). Still encountered in older maps and legal property descriptions. Can differ up to 90m from WGS84 in western US.
About NAD83 (lat/lng)
North American Datum 1983 (EPSG:4269). Standard geographic reference for USA, Canada, Mexico. Drifts slowly relative to WGS84 (~1m difference in typical use). Base for all US survey products.
Frequently Asked Questions
What is the difference between NAD27 and NAD83 (lat/lng)?
NAD27 (EPSG:4267) is geographic and based in USA, while NAD83 (lat/lng) (EPSG:4269) is geographic based in USA. Legacy US datum (Clarke 1866 ellipsoid). Still encountered in older maps and legal property descriptions. Can differ up to 90m from WGS84 in western US. In contrast, standard geographic reference for usa, canada, mexico. drifts slowly relative to wgs84 (~1m difference in typical use). base for all us survey products.
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 NAD27, enter coordinates as decimal degrees in the format "lat, lng" (e.g. 45.4642, 9.1900). 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:4267&to=EPSG:4269&coords=lat,lng for programmatic access. It returns the transformed coordinates as JSON.