Aviation Altimeter is an extremely simple, fun and accurate tool for tracking your altitude both on the ground and in the air. GPS measurements calibrate your initial altitude and track your altitude over time, with the option of specifying a manual altitude if you know it.

For iPhone 6 and 6 Plus users, along with iPad 2 Air and now Apple Watch users, the new built-in barometer allows for even more accurate altitude measurements, along with a local pressure reading in hectopascals or millimetres of mercury. Your GPS location may be used to initially calibrate your altitude against the current barometric pressure, at which point the barometer takes over for extremely accurate altitude readings. As with GPS based altitude readings, you have the option to manually calibrate your altitude.

Coming soon:
* Vertical speed indicator.
* Calibrate based on known barometric pressure.