Pixel Watch 3 vs OnePlus Watch 3 heart rate tracking: A clear winner

I’ve been testing the Google Pixel Watch 3 and the OnePlus Watch 3 extensively since they were announced. Both smartwatches offer the latest Wear OS, a beautiful display, and a sleek build, and for day-to-day use, I’d happily wear either one. But the two watches couldn’t be any more different in a few key areas.

The OnePlus Watch 3 has impressed me with its battery life, proving itself as a true multi-day device. When I’m wearing it, this kind of convenience is a luxury. But the big praise it gains in endurance, the OnePlus Watch 3 loses in heart rate tracking, especially compared to the Pixel Watch 3, which offers some of the most accurate heart rate tracking in the game. That’s why Google has earned a permanent spot on my wrist.

Curious to see how much more accurate the Pixel Watch 3’s heart rate tracking is? I’ve got the tests to prove it.

Both the Pixel Watch 3 and the OnePlus Watch 3 are fantastic devices, each building on the success of its predecessor. However, in my reviews, I rated the Pixel Watch 3 slightly higher, awarding it four and a half stars and the OnePlus Watch 3 only four. I didn’t knock the OnePlus watch half a star for heart rate monitoring alone — there are some other shortcomings as well — but its inaccurate tracking was certainly a factor. During my review, it failed to keep up with my chest strap, showing only limited improvement from the OnePlus Watch 2.

With that said, chest straps are widely regarded as the most reliable tools for heart rate monitoring, and not many wrist-based wearables can deliver the same level of accuracy. To find out how the OnePlus Watch 3 directly compares to its competition, I decided to test the watch against the best Google has to offer.

I tested both smartwatches across a series of workouts, including activities like running, walking, weight lifting, rowing, and yoga. With added wrist movement, the latter workout types can be particularly tricky for wrist-based wearables. I also tracked some interval workouts to see how each device handled changing intensities. For consistency, I kept my chest strap on throughout the sessions to use as a reliable baseline for comparison.

The following graphs represent my findings on each device’s heart rate accuracy. The TLDR? Google delivers.

In the graphs above, you can see how both watches compare to a trusted heart rate-tracking chest strap, the Polar H10. While the Pixel Watch 3 shows nearly perfect alignment, the OnePlus Watch 3 did not perform as well. Throughout the high-intensity workout, the watch consistently lagged, showing peak heart rates late as I revved up my intervals. This wasn’t a great start for OnePlus, but like I said, I was most interested in seeing how the watches performed head-to-head.

For the rest of my workouts, I wore both watches (on opposite wrists) along with a dedicated chest strap. The graph above shows another interval workout, this time on a rowing machine. The Pixel Watch 3 clearly tracks more closely with the chest strap, while the OnePlus watch records several inconsistencies.

When I took all three devices to the gym for a weight training session, things didn’t improve for OnePlus. The zoomed-in section above shows how both watches struggled to nail my heart rate compared to the chest strap. This is fairly expected for this activity type, as the strain on your wrist makes it a tough workout for smartwatches. However, once again, Google’s watch maintained closer alignment than OnePlus, even though it didn’t produce perfect data.

It’s clear that while the OnePlus Watch 3 can handle moderate workouts like runs and walks, it is not quite as reliable as the Pixel Watch 3 for detailed tracking. Notably, both watches and the Polar strap had very similar average heart rates for all of my workouts. This suggests that the OnePlus Watch is capable of big-picture tracking, even if it can’t always provide pinpoint accuracy. As someone currently training with an eye locked onto heart rate zones, though, I’m hoping for the most accurate readings I can find. Likewise, for serious athletes looking closely at their own training data and trends, exact tracking is key.

For the average user, the OnePlus Watch 3’s heart rate tracking will likely be sufficient. Its broad view heart rate data (like average bpm) aligns with what you’d expect from similar devices, and its heart rate zones are useful during workouts, with high heart rate alerts as a handy feature. However, athletes seeking more precise fitness tracking or people like me closely tracking their heart rate during workouts might want to consider other options. At the detailed level, the OnePlus Watch 3’s performance is inconsistent compared to similarly priced competition, especially the Pixel Watch 3. A close look reveals fluctuating readings, delayed spikes, and less reliable data overall.

In contrast, the Pixel Watch 3 stands out to me with exceptional heart rate tracking. Thanks to an advanced sensor and improved algorithms, it provides precise and reliable heart rate measurements through various workout types. It proved equally reliable, tracking everything from burpees to light walks. Google offers data that even the most detail-oriented athletes can trust.

Not everyone shopping for a smartwatch will care about digging into the nitty gritty of their heart rate tracking. As I mentioned, the OnePlus watch is good enough for most. For now, though, my heart is taken by Google’s sensors.