Altimeter
Free online altimeter: measure terrain elevation (metres above sea level) at your current location using the GPS on your phone, tablet or computer. If the device provides it, it also shows GPS altitude.
Tap Update and allow location access.
If you tapped Block, reloading the page will not show the prompt again: the browser remembers the denial. Open the lock icon (on iPhone the AA button) in the address bar → Location → Allow, then tap Try GPS again.
Without GPS: search for a place or enter coordinates
Write it like this: street and number, city (Baker Street 221B, London). A town name is enough: London or Rome, Italy.
Location from the device GPS; terrain height from Open-Meteo Elevation (Copernicus DEM, ~90 m). GPS altitude, when present, is the phone height and may differ. Versione italiana: Altimetro.