Ellipsoidal to Orthometric Height Converter
A free, browser-based converter. Runs entirely in your browser — no sign up, nothing stored.
100% FreeRuns in your browserIntermediate
Enter Values
Enter your values and press Calculate to see results.
How to use this calculator
- Enter the ellipsoidal height (from GPS/GNSS).
- Enter the geoid separation N for your location.
- Press Calculate for the orthometric height.
How it works
Orthometric height (above mean sea level) H = ellipsoidal height h − geoid separation N.
Worked example
h = 45.2 m, N = −30.5 m. H = 45.2 − (−30.5) = 75.7 m above the geoid.
Frequently asked questions
Where do I get the geoid separation N?
From a national geoid model (e.g. AusGeoid, GEOID18). GNSS gives ellipsoidal height; subtract N to get height above sea level.
Related tools
Tip: Enter any known values to calculate the remaining results.
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