Earth-centred, Earth-fixed coordinates
ECEF (geocentric) coordinates give a position as X, Y and Z in metres from the centre of the Earth: Z along the rotation axis, X through the Greenwich meridian at the equator and Y through 90° E. GNSS receivers compute in this frame, and datum transformations such as Helmert work on it.
The converter uses the WGS 84 ellipsoid and the EPSG formula (method 9602), checked against the EPSG worked example to the centimetre. The result shown uses an ellipsoidal height of 0 m; paste X Y Z to get latitude, longitude and the height back.
Frequently asked questions
How do I convert ECEF to latitude and longitude?
Paste the three numbers, for example 3771793.97 140253.34 5124304.35. The converter recognises them as X, Y, Z in metres and shows latitude, longitude and every other format.
Why is Z smaller than the Earth's radius at the poles?
The Earth is flattened: the polar radius is about 6,357 km against 6,378 km at the equator, so Z at the pole is about 21 km less than X at the equator.