Last weekend, I put on five fitness smartwatches, drove to Mount Diablo State Park in California, and hiked about 2,100 feet to the top. Because? Deciding which brand of smartwatch (Apple, COROS, Garmin, Polar or Samsung) was most accurate at tracking elevation.
Most high-end smartwatches feature a barometric altimeter to judge elevation gain during outdoor workouts. Altimeters use air pressure changes to calculate elevation changes in coordination with GPS data. But some are more accurate than others and most brands don’t allow you to calibrate your starting position manually.
I’ve wanted to try this for some time, ever since my experiment last year when I used six smartwatches for 6,000 steps to see which one was closest to the real number. Since then, I’ve also done several GPS accuracy tests with multiple watches for reviews, but they’ve all been two-dimensional tests: I’ve never known how accurate my watch is when it tells me I’ve climbed X feet or Y. flights of stairs.
For my test, I chose three watches that I’ve already reviewed (COROS PACE 3, Garmin Forerunner 965, and Samsung Galaxy Watch 6 Classic) along with two that I’m currently reviewing, the Apple Watch Ultra 2 and Polar Vantage V3.
Apologies to hikers with favorite brands I didn’t bring; My arms, no matter how thin they are, have a limit of space. Carrying and attaching five watches was more than enough, and I got plenty of sideways glances at the trail as it was.
Additionally, some of my favorite wearables (like the Fitbit Charge 6) don’t have any altimeter, meaning they can’t be relied on for elevation data aside from GPS estimates.
Luckily, you can easily test the accuracy of your own smartwatch if you want!
Simply choose a hike on a site like Alltrails, like the Mount Diablo hike via Summit Trail, and look at the minimum and maximum elevation, along with the total elevation gain. Then, walk around yourself and compare your watch results with reality.
The following table shows the lifting accuracy test results of my smart watch:
|Total lift gain
|Accurate GPS data (AllTrails)
|Apple Watch Ultra 2
|CHORUS RHYTHM 3
|Garmin Forerunner 965
|Samsung Galaxy Watch 6 Classic
Note: You’ve probably noticed that a row of data is missing. This is because at some point while descending from Mount Diablo, my Polar Vantage V3 crashed, displaying an endless loop of the Polar logo, and then factory reset when I got home. The Polar subreddit shows that other people have had similar problems in the past.
Fortunately, I took a photo near the peak that shows my elevation (3,729 feet) and total gain (2,018 feet) at the time. Add another 100 feet or so of climb, and the Vantage V3 was probably pretty close to what my other watches were showing; I just can’t give exact data, especially without the initial elevation. I’m really disappointed that this bug ruined my test!
Determining the ‘best’ smartwatch altimeter
We have three metrics to help judge which smartwatch is best for elevation accuracy. Let’s start with the minimum elevation, which is the initial auto-calibration result the smartwatch gets when you start a workout.
Garmin and Apple miraculously tied here, both within nine feet of each other. COROS was 34 feet short, or 25 feet short of Garmin, but that’s nothing compared to Samsung’s result, which fell 261 feet short.
As for maximum elevation, Garmin came within eight feet of the official summit number. Basically, although Garmin deviated by a few meters each time, the gap between the minimum and maximum (2080 feet) was only a foot different from the official data (2,079 feet).
COROS’s maximum result, 3,825 feet, was 24 feet short; However, again, if you look at the total difference (2,089 feet), that’s only 10 feet from the satellite data, which most hikers will happily accept.
Apple’s maximum elevation data had me hovering about 24 feet above Mount Diablo, and its total difference (2094) is 15 feet above. Considering all the smarts you get with an Apple Watch Ultra 2 compared to most fitness smartwatches, that’s a minor discrepancy that watchOS fans probably won’t mind.
You could also say that the Galaxy Watch 6 Classic’s total elevation difference (2,097 feet) is perfectly respectable, but the maximum elevation was just as absurdly off the mark as the minimum elevation. Samsung had an Alti-Barometer app in the Galaxy Store that would have fixed this issue, but it was designed for Tizen OS and does not work properly with Wear OS.
Lastly, we can look at the total elevation gain, which (to clarify) is different from the subtracted sums above because additional elevation is gained each time the trail goes up and down.
At first glance, the Apple Watch Ultra 2 surpassed this metric, exceeding just eight feet. The problem is that I went up and down the stairs to the top a couple of times, as well as taking some side roads with mini-hills that added unnecessary ups and downs.
So while the Garmin Forerunner 965 and the COROS PACE 3 measured an additional 92 feet of ascent, I’m wondering if my actual result was somewhere between these two and the Ultra 2. The fact that they both got the exact same result was another surprise . .
The nice thing about the latest Garmin Forerunner watches, the PACE 3 and the Apple Watch Ultra 2, is that they all feature dual-band GPS tracking. If the mountain you’re climbing blocks the line of sight of the nearest GPS satellite, they can use another satellite to calibrate your position. And since the watches use GPS to boost the altimeter results, that means you’re very likely to get something near to a precise result.
If you’re using a GPS-only watch like the Galaxy Watch 6 Classic, your elevation results could end up being trickier despite the built-in altimeter. The incorrect initial elevation may not matter from a practical point of view, but the fact that it did not report my elevation gain by at least 100 feet it is less forgivable.
I hope Samsung fixes its fitness problems in 2024 and the Galaxy Watch 7 Pro is more reliable. In the meantime, I’m very happy with the performance of Garmin, COROS and Apple in my test. Garmin won by specific elevation numbers, Apple won (maybe) by elevation gain, and COROS was close on both counts.
Instead of supporting a clear winner, I want as many brands as possible to provide accurate results so hikers and cyclists have a wide variety of options.
Yeah If you’re currently in the market for a new smartwatch, bike computer, or wearable GPS, my recommendation is to don’t assume that an altimeter on the spec sheet is a sure sign of reliability. Save your receipt, get your new watch to the track as soon as possible, and make sure you get results that are reasonably accurate.