We all have our ups and downs, but some of us like to measure that vertical movement, which is why there’s a whole boatload of altimeter apps. You probably use your phone’s location to do 2D street-level navigation all the time, but those same satellites can also help you find your distance above sea level (altitude, not to be confused with elevation, which is the earth’s distance above sea level). Paired with a barometric pressure sensor and a data connection (if there’s one available), your phone can get you surprisingly accurate altitude readings.
How do phones measure elevation?
A lot of the earth’s elevation changes have already been mapped thanks to geospatial survey projects, so most latitude-longitude coordinate pairs can be used to look up the corresponding elevation. This generally requires data, though, and is only accurate for you personally if you’re standing on the ground.
How do phones measure altitude?
The most important altitude measurement tool in your phone’s arsenal is the GNSS/GPS receiver. If your phone can find at least four satellites, with one directly overhead, you can usually get an altitude reading accurate to within 10 to 20 meters (35 to 70 feet). Having good satellite reception isn’t always guaranteed, though, and while GPS-based altitude works most of the time, it can still be subject to fairly large errors.
That’s why many modern phones are also equipped with barometric pressure sensors (barometers). Because gravity pulls everything down towards the earth, including the atmosphere, pressure gets lower as your altitude increases. Measuring this change helps your phone figure out how far up or down you’ve gone.
Shifting weather can also affect atmospheric pressure, though, so most altimeter apps will try to get the most current pressure data from a nearby meteorological station. This gives the app something to compare the pressure changes to. Barometer-based altitude measurements can still work without a data connection, but you may have to calibrate it manually.
There are tons of altimeter and elevation apps for iPhone and Android, and honestly, their accuracy doesn’t vary much. The best apps, though, like the ones below, go beyond simple measurement to provide other environmental data and tracking features.
1. Altimeter & Altitude Widget
This app from DS Software uses location, barometer, and geospatial survey data to help you get accurate elevation and altitude readings, plus it comes with an array of maps and a feature that allows you to record and graph your altitude trends. Being able to switch easily between elevation (The SRTM and USGS settings are both for elevation) and altitude (GPS and Bar) is a great feature, since comparing the two readings can help you get a sense for how accurate your altitude is. If you have an onboard barometer, the app also provides an array of calibration options, allowing you to get the data from the nearest airport or set it manually. Its level of detail, variety of elevation/altitude settings, and tracking features make it an excellent choice as a workhorse altimeter.
2. Altimeter GPS – Hike & Trek
This iOS app comes with the standard altimeter, barometer, and compass, plus a pedometer and journey tracker so you can visualize your distance and altitude changes. There’s even an SOS feature that can automatically send someone your location in an emergency. It’s the trip tracking that sets this app apart, though, as a lot of iOS altimeters don’t come with that feature.
3. Altimeter Ler
This app’s design makes you feel like you’re in an airplane cockpit, but you can’t argue with the rich data you get out of it. Altimeter Ler gives you a full readout of our location and environmental conditions, plus a variety of maps and good tracking features. It can calculate altitude based on both GPS and barometer readings and even tells you the estimated error of the GPS data you’re getting. It doesn’t have visualization tools to track your altitude changes or elevation data, but it comes with enough other features to make up for those shortfalls.
4. My Altitude
Disclaimer first: this app (Android, iOS) has some issues with Android (it kept me at 0 meters the whole time), but it’s probably the best altitude app for the iPhone. You get the whole package here: altitude, coordinates, barometric pressure, water boiling point, weather – even NOAA data you can download to use the app offline. It doesn’t come with any tracking or graphing features, but it does have a tool that lets you take a photo with attached coordinates, altitude, and time.
5. Altimeter (by EXA)
EXA Tools’ altimeter for Android doesn’t provide a lot of extra data, but its interface is easy to read and its tracking feature might actually be one of the best on this list thanks to its nicely-presented altitude-change graph. It comes with a lot of ads (you can get rid of these by going premium), but they’re not unmanageable, and the app itself works well.
Should I just get a real altimeter?
If “Ain’t no mountain high enough” is less of a song lyric and more of a life motto for you, you might have your eye on a non-phone altimeter. The good news is that this probably isn’t necessary if your phone has a decent GNSS chipset and a barometer, as tests have shown smartphones and altimeters to have roughly similar accuracy. If your phone is missing a barometer, though, you may get spottier results using location satellites alone, so either a hardware upgrade or a separate altimeter might be in order if you really care about accuracy.