Ever since the Fitbit Air launched in May 2026, the conversation has almost always been about its price point. Reviews have been calling it a "$100 Whoop killer," and even we named it the best Whoop alternative for the rest of us. But one thing everyone seems to be missing is whether the tracking is actually any good.
Sure, it costs less, but does the Fitbit and Google name automatically mean it's great at tracking your health? Does it even give insights that are, first of all, accurate and then actually useful?
I've been tracking my sleep with both the Fitbit Air and the Whoop MG for a week, and the Fitbit Air actually held up much better than I expected. It's not perfect, though, and there are a few things you should know before buying one.
Here's how I tested both trackers side by side
Before we get into the numbers, there's one thing worth knowing upfront: I've been using the Whoop MG for over a year now. It's been my primary fitness and health tracking device for that entire time, which means it has a lot more context about my body compared to the Fitbit Air.
I got the Fitbit Air around June 16 and started properly testing it from the night of June 17. For this test, I wore the Fitbit Air on my left, non-dominant wrist, while my Whoop MG has been on a bicep band on the same arm for the past three months. I tracked a full week across both devices from June 17 to June 25, with two nights being an exception where I actually slept without any of the bands because I fell sick.
Before we dive into the numbers, though, it's worth knowing that since the Fitbit Air was brand new out of the box, it was still building its baseline during the first couple of nights.
It's also worth noting that wearing the Whoop MG on the bicep rather than the wrist does influence readings. Both are valid measurement points, but it's commonly believed that less movement leads to more accurate results.
The wrist moves around a lot, while the bicep stays relatively still, so the Whoop data could be slightly more accurate because of that, though I can't say for certain. Either way, the Fitbit Air doesn't offer a bicep band yet, so if a bicep option is something you need, the Whoop MG is currently the only choice.
Fitbit needed a few nights before the data made sense
As expected, the Fitbit Air took a couple of days to calibrate to my body and sleep patterns. I wasn't expecting it to agree with the Whoop MG right from the first night, and that was pretty obvious in the data. On day one, there was almost a one-hour difference in total sleep. Fitbit Air logged just 5 hours and 15 minutes of sleep, while the Whoop MG recorded around 6 hours and 15 minutes.
Thankfully, things improved quickly after that. From the second night onward, the two trackers became much more consistent. On the final two nights of my testing (June 22 and June 25), both devices recorded roughly seven hours of sleep on one night and around seven and a half hours on the other, with only about a 15-minute difference.
I'd call that accurate enough for tracking total sleep duration. If all you care about is knowing how long you slept, the Fitbit Air becomes much more reliable after a few days of wear.
Night | Whoop MG | Fitbit Air | Difference |
|---|---|---|---|
Jun 17 | Duration: 6h 15m | Duration: 5h 15m | Duration: 60 min |
Jun 18 | Duration: 6h 39m | Duration: 6h 53m | Duration: 14 min |
Jun 19 | Duration: 6h 56m | Duration: 7h 33m | Duration: 37 min |
Jun 22 | Duration: 6h 32m | Duration: 6h 48m | Duration: 16 min |
Jun 25 | Duration: 7h 17m | Duration: 7h 34m | Duration: 17 min |
Sleep stages, though, are a completely different story. Even after a week, both devices continued to disagree quite a bit on deep sleep and REM sleep. You can see from the table above that there are some pretty noticeable differences between the two, despite both devices tracking the exact same nights.
Which one is actually right? Honestly, it's hard to tell after just a week of testing. A longer testing period might reveal whether the two begin converging over time, but that is something I'll give one or two months to test.
It's also worth noting that placement could be playing a role here. As I mentioned above, I wore the Whoop MG on my left bicep while the Fitbit Air stayed on my left wrist, and this might have led the trackers to produce slightly different readings.
One area where the Fitbit Air clearly felt better to me, however, was the representation of the data collected overnight.
Fitbit's app actually won me over
I've said this before, and I'll say it again. While Whoop has become popular with casual users, it's still a product built primarily for athletes. That means the moment you open the app after waking up, you're greeted with a wall of numbers, graphs, and recovery metrics.
I can't believe I'm saying this, but I actually think Google has done a great job with the Google Health app that powers the Fitbit Air, even though plenty of Fitbit users might disagree with me.
I don't want to wake up and immediately analyze a dashboard full of metrics. Instead, Fitbit Air gives me a quick summary of how I slept, and for most mornings, that's all I need to know whether I had a good night's sleep or not. I also like that I can tell the app when I don't agree with how I'm feeling, rather than blindly accepting the data.
One thing I also noticed during my testing was how much faster Fitbit Air processes sleep data. Most mornings, it gave me my sleep summary within five to seven minutes of waking up.
The Whoop app, on the other hand, often took much longer. There were days when I didn't get my sleep report for nearly 30 minutes, and sometimes I even had to manually end the sleep session before it would process the data.
Verdict
Overall, I still think the Fitbit Air offers a better experience for the average user. Sure, the data differed from Whoop, but that's true of almost every consumer sleep tracker. None of these devices are clinical-grade after all.
After a week of wearing both trackers, I don't think sleep tracking alone is a good enough reason to spend significantly more on a Whoop. Once the Fitbit Air had a few nights to calibrate, its total sleep tracking was consistently close enough that I stopped paying attention to the differences.
What you're really paying the Whoop premium for isn't better sleep tracking. It has other features as well, like ECG, blood pressure insights, strain tracking, and a whole recovery ecosystem built for athletes. If those features matter to you, the subscription makes sense.
But if your main priority is simply understanding how well you slept each night, I honestly think the $100 Fitbit Air gets you most of the way there, with a friendlier app experience and for a fraction of the yearly cost.
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