Alt-O-Meter

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 airplane's 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.