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Convert NAD27 to NAD83

Convert coordinates from NAD27 (EPSG:4267) to NAD83 (EPSG:4269) — official EPSG transformation parameters, accuracy and area of use, with a free in-browser converter.

Direct link to this transformation: epsgtransform.com/transform/epsg-4267-to-epsg-4269

Official EPSG transformations from NAD27 to NAD83

The EPSG Geodetic Parameter Dataset defines 9 transformations between NAD27 (EPSG:4267) and NAD83 (EPSG:4269). Each applies to a specific area — pick the one whose area of use covers your data.

NAD27 to NAD83 (1)

EPSG:1241±0.15 mBest accuracy
Method:
NADCON
Area of use:
USA - CONUS including EEZ
Scope:
Transformation of coordinates at 0.2m level of accuracy.

Grid files: conus.lasconus.los

Uses NADCON method which expects longitudes positive west; EPSG GeogCRS NAD27 (code 4267) and NAD83 (code 4269) have longitudes positive east. For application in Gulf of Mexico refer to IOGP report 373-26.

NAD27 to NAD83 (7)

EPSG:8555±0.15 m
Method:
NADCON5 (2D)
Area of use:
USA - CONUS and GoM
Scope:
Geodesy.

Grid files: nadcon5.nad27.nad83_1986.conus.lat.trn.20160901.bnadcon5.nad27.nad83_1986.conus.lon.trn.20160901.b

NADCON5 method expects longitudes 0-360°; source and target CRS longitudes in range ±180°. Accuracy at 67% confidence level is 0.15m onshore, 1m nearshore and undetermined farther offshore. For application in Gulf of Mexico refer to IOGP report 373-26.

NAD27 to NAD83 (2)

EPSG:1243±0.5 m
Method:
NADCON
Area of use:
USA - Alaska including EEZ
Scope:
Geodesy.

Grid files: alaska.lasalaska.los

Uses NADCON method which expects longitudes positive west; EPSG GeogCRS NAD27 (code 4267) and NAD83 (code 4269) have longitudes positive east. May be used as transformation to WGS 84 - see NAD27 to WGS 84 (85) (code 15864).

NAD27 to NAD83 (8)

EPSG:8549±0.5 m
Method:
NADCON5 (2D)
Area of use:
USA - Alaska
Scope:
Geodesy.

Grid files: nadcon5.nad27.nad83_1986.alaska.lat.trn.20160901.bnadcon5.nad27.nad83_1986.alaska.lon.trn.20160901.b

Uses NADCON5 method which expects longitudes positive east in range 0-360°; source and target CRSs have longitudes positive east in range -180° to +180°. Accuracy at 67% confidence level is 0.5m onshore, 5m nearshore and undetermined farther offshore.

NAD27 to NAD83 (4)

EPSG:1313±1.5 m
Method:
NTv2
Area of use:
Canada - NAD27
Scope:
Transformation of coordinates at 1m to 2m level of accuracy.

Grid file: NTv2_0.gsb

Uses NTv2 data files. Replaces NTv1 (transformation code 1312) except in Quebec. Input expects longitudes to be positive west; EPSG GeogCRS NAD27 (code 4267) and (code 4269) have longitudes positive east. May be used as tfm to WGS 84 - see code 1693.

NAD27 to NAD83 (6)

EPSG:1573±1.5 m
Method:
NTv2
Area of use:
Canada - Quebec
Scope:
Transformation of coordinates at 1m to 2m level of accuracy.

Grid file: NA27NA83.GSB

Also distributed with file name QUE27-83.gsb. Replaces NAD27 to NAD83 (5) (code 1462). Uses NT method which expects longitudes positive west; EPSG GeogCRSs NAD27 (code 4267) and NAD83 (code 4269) have longitudes positive east.

NAD27 to NAD83 (9)

EPSG:9111±1.5 m
Method:
NTv2
Area of use:
Canada - Saskatchewan
Scope:
Geodesy.

Grid file: SK27-83.gsb

NAD27 to NAD83 (3)

EPSG:1312±2 m
Method:
NTv1
Area of use:
Canada - NAD27
Scope:
Historic record only - now superseded - see remarks.

Grid file: NTv1_0.gsb

Uses NTv1 method. Replaced in Quebec by code 1462 and elsewhere in 1997 by NTv2 (transformation code 1313). Input expects longitudes to be positive west; EPSG GeogCRS NAD27 (code 4267) and NAD83 (code 4269) have longitudes positive east.

NAD27 to NAD83 (5)

EPSG:1462±2 m
Method:
NTv1
Area of use:
Canada - Quebec
Scope:
Historic record only - now superseded - see remarks.

Grid file: GS2783v1.QUE

Densification for Quebec of code 1312. Replaced by NAD27 to NAD83 (6) (code 1573). Uses NT method which expects longitudes positive west; EPSG GeogCRSs NAD27 (code 4267) and NAD83 (code 4269) have longitudes positive east.

Convert EPSG:4267 to EPSG:4269 in code

The same transformation with common GIS tools and libraries:

from pyproj import Transformer

transformer = Transformer.from_crs("EPSG:4267", "EPSG:4269", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)

Source: EPSG:4267 — NAD27

geographic system using latitude and longitude on an ellipsoid · Area of use: North America - NAD27

+proj=longlat +datum=NAD27 +no_defs +type=crs
More about EPSG:4267 →

Target: EPSG:4269 — NAD83

geographic system using latitude and longitude on an ellipsoid · Area of use: North America - NAD83

+proj=longlat +datum=NAD83 +no_defs +type=crs
More about EPSG:4269 →

Frequently asked questions

How accurate is converting NAD27 to NAD83?
The most accurate official EPSG transformation between these systems is accurate to about ±0.15 m within its stated area of use. Browser-based converters approximate datum shifts with Helmert parameters; for surveying-grade work apply the official transformation (including the grid-shift files listed below) 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:4269 to EPSG:4267 →