ECEF ↔ Lat/Long Converter
Convert between Earth-Centered Earth-Fixed (X, Y, Z metres) and geodetic latitude/longitude/height on the WGS84 ellipsoid. Bowring's closed-form algorithm. Free, runs in your browser.
WGS84 constants used
The WGS84 reference ellipsoid is defined by a semi-major axis of a = 6,378,137.0 m, a flattening of 1/f = 298.257223563, giving the first eccentricity squared e² = 0.00669437999014. The semi-minor axis is b = 6,356,752.3142 m. All ECEF coordinates returned by this tool use this ellipsoid.
Frequently Asked Questions
What is ECEF?
ECEF stands for Earth-Centered, Earth-Fixed — a Cartesian coordinate system whose origin is at the Earth's centre of mass, with the X axis pointing toward the prime meridian at the equator, the Y axis toward 90°E, and the Z axis toward the North Pole. Coordinates are X, Y, Z in metres. It is the natural format for GPS raw measurements, satellite orbit propagation, and aerospace navigation.
How do you convert lat/long to ECEF?
On the WGS84 ellipsoid: X = (N + h) cos φ cos λ, Y = (N + h) cos φ sin λ, Z = (N(1 - e²) + h) sin φ, where N = a / √(1 - e² sin²φ) is the radius of curvature in the prime vertical, a = 6378137 m and e² = 0.00669437999014 are WGS84 constants, and h is height above the ellipsoid.
How do you convert ECEF back to lat/long?
This tool uses Bowring's closed-form algorithm, which is accurate to millimetres across the full ECEF domain and faster than the iterative method. It returns geodetic latitude, longitude, and height above the ellipsoid.
What about ENU / NED local frames?
ECEF is global; for local navigation (e.g. drones, robots) you typically convert to a local tangent-plane frame: ENU (East-North-Up) or NED (North-East-Down). This tool focuses on ECEF ↔ geodetic, the most common conversion. From geodetic you can derive ENU with a separate rotation step.