Source: EPSG:4123 — KKJ
geographic system using latitude and longitude on an ellipsoid · Area of use: Finland - onshore
+proj=longlat +ellps=intl +towgs84=-96.062,-82.428,-121.753,4.801,0.345,-1.376,1.496 +no_defs +type=crsMore about EPSG:4123 →
Convert EPSG:4123 to EPSG:3857
Online coordinate converter from KKJ (EPSG:4123) to WGS 84 / Pseudo-Mercator (EPSG:3857). Enter your source coordinates and get the result instantly. All transformations happen in your browser — no data is sent to any server.
Convert EPSG:4123 to EPSG:3857 in code
The same transformation with common GIS tools and libraries:
from pyproj import Transformer
transformer = Transformer.from_crs("EPSG:4123", "EPSG:3857", always_xy=True)
x, y = transformer.transform(-73.9857, 40.7484)
print(x, y)Target: EPSG:3857 — WGS 84 / Pseudo-Mercator
projected system measured in linear units (typically metres) · Area of use: World - 85°S to 85°N
+proj=merc +a=6378137 +b=6378137 +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null +wktext +no_defs +type=crsMore about EPSG:3857 →
Frequently asked questions
- How accurate is converting KKJ to WGS 84 / Pseudo-Mercator?
- Projection-only conversions are accurate to floating-point precision. If a datum shift is involved, browser-based tools use Helmert parameters which are accurate to roughly 1-5 m; for surveying-grade work apply the official grid-shift 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.