Alt-O-Meter app for iPhone and iPad

Alt-O-Meter uses the barometer (air pressure sensor) in your late-model iPhone or iPad to calculate your precise height above sea level. Great for hiking, skiing, driving through mountain passes, flying, and more!

• Reads ambient air pressure for a more precise reading than GPS.
• Realistic, retro style. Looks like a classic airplanes altimeter!
• Automatically calibrates for local atmospheric pressure.
• ...also allows precise user calibration (optional; for advanced users)
• Uses GPS hardware in devices that lack a barometer.
• Completely free! No ads or in-app purchases.