In the era before modern smartwatches, Fitbit's name became synonymous with wearable fitness trackers. Full-fledged smartwatches have become the norm as consumers have demanded more and more from wearables, and Fitbit stepped in with the Ionic and Versa smartwatches a few years ago. I had high hopes that Fitbit would continue to improve and provide Android users a viable alternative to the increasingly frustrating Wear OS experience, but the Sense has some of the same shortcomings and bugs I remember from the Ionic. The Sense also has its own raft of new glitches that I find equally annoying. At the same time, Fitbit promises this watch can do so many things! It'll take your temperature, measure your blood oxygen, track workouts, and on and on. None of it feels quite done, though, and this is not a cheap watch.

The higher $329 asking price probably has a lot to do with the plethora of sensors, each of which provides a bit more data. However, some of them don't seem very accurate or convenient to use, and Fitbit is adding all this hardware before it's even worked out some basic flaws in its software. There's enough wrong that the Sense is not worth the asking price, and it won't be unless Fitbit can squash the bugs and deliver on promised improvements.


Sensors Temperature, EDA, ECG, heart rate, blood oxygenation (SpO2), accelerometer, gyroscope
Battery Up to 6 days
Display 1.58-inch 336 x 336 OLED
Connectivity Wi-Fi (802.11b/g/n 2.4GHz), Bluetooth 5.0, NFC, GPS
Measurements 40.48mm x 40.48mm x 12.35mm, 45.9g (with band)

The Good

Display It's sharp enough, gets bright outdoors, and Fitbit does a good job of hiding the bezels.
Meaningful Fitbit OS improvements More reliable notifications, better shortcuts, always-on display, and more.
Battery The Sense lasts the better part of a week (without always-on display).
Bands The quick-release design makes it easy to wap bands,

The Not So Good

Sensors The EDA and SpO2 sensors are annoying to use, and I don't know that I believe the numbers.
Music Music storage only with Deezer and Pandora Plus, controlling playback on a phone requires extra steps.
The "solid state" button It's so much less easy to use than a real button.
Bugs I've seen several hard reboots, syncing is hit and miss, workout detection seems broken, and the watch is just generally laggy.
Bands again You can only use bands designed for Fitbit's custom connector.
Missing features No Google Assistant support or phone calls until a later date.
Value $329 for this experience feels very high.

Design, hardware, what's in the box

The Sense has more in common with the Versa than it does with the Ionic, which I have to admit bums me out. I initially thought the Ionic was quite ugly, but the funkiness of the design grew on me, in large part, because it doesn't look like an Apple Watch. Alas, the Sense looks like an Apple Watch, just a bit more rounded. If you look closely, you'll also see that the 1.58-inch OLED screen has much larger bezels than Apple's wearable, but Fitbit does a pretty good job of hiding that with dark backgrounds. The display itself is excellent for a smartwatch. It's sharp enough for a tiny screen on your wrist, and it gets very bright outdoors.

The case is the same matte aluminum and Gorilla Glass as past watches, and it's still water-resistant to 50m. The bottom half of the watch bulges out a bit to keep the sensors in contact with your skin, but that's par for smartwatches. There are also quick-release latches for the band down there. Annoyingly, these are yet another custom connector for Fitbit, so you can't just use any old band. That said, it's very quick to swap between multiple styles, and the stock silicone band is very nice—almost Apple nice.

Like the Versa 2, there's a single button on the left edge of the watch. Well, sort of. The Sense has what Fitbit calls a "solid state button," which is a fancy way to say there's a pressure-sensitive region on the side. There's a divot to help you find the faux button by feel, but it's in a somewhat awkward spot, just past where the case starts to taper. When I'm looking at the side of the watch, I can nail the button almost every time. When I'm not, I often have to squeeze two or three times to find the sweet spot.

The Sense doesn't come with any unexpected extras. You get the watch itself, a magnetic charging cable (no wall adapter), and two sizes of silicone bands. I like that Fitbit still includes both sizes, and they should fit a wide range of wrists. I have rather bony wrists, and I'm near the end of the small band.

Software, battery, and features

The Fitbit Sense is all about the sensors—that's what sets it apart from the Versa 3. It's the first Fitbit smartwatch with an ECG sensor, for example. That means you can launch the ECG app to check for abnormal heart rhythms, which is technically impressive but not of much use to most people. If it could take these readings in the background, maybe, but how often are you going to remember to open the app? Granted, Apple has the same requirement on the Apple Watch, so I can't be too hard on Fitbit here. I can, however, be hard on Fitbit for the way it implemented the SpO2 sensor.

When I started using the Sense, it was totally unclear how I was even supposed to check my blood oxygenation. There's no app for it, and none of the daily stats include this metric. As it turns out, you can only use the SpO2 at night when you have a specific watch face selected. If you don't do that, you don't get the data. Fitbit says it will eliminate that requirement in a future update, but I'm not holding my breath. The data I got from the SpO2 sensor when I did remember to choose the right watch face wasn't very impressive. On several occasions, the readings suggested I was near death, with blood oxygenation in the low 90s. This is, as far as I'm aware, untrue (famous last words, maybe).

There's also an EDA (electrodermal activity) sensor, which measures the electrical characteristics of your skin. This can indicate stress levels, along with heart rate, which the Sense also measures—it's a bit like a polygraph, and like a polygraph, Fitbit's stress management scores are very vague and open to interpretation. It also takes several minutes for each EDA scan, during which you need to remain still with your hand covering the watch. So, I don't imagine I'll do this very often. The step tracking and heart rate numbers do seem roughly accurate to me, and sleep tracking is at least believable. Although, the true accuracy of sleep tracking is disputable.

The Sense can store health data for a few days, but ideally, you want to sync it with your phone regularly. Fitbit has struggled to make syncing reliable, in my experience with past watches. Things seem marginally better with the Sense, but there are still issues. Actions that should be simple, like switching watch faces, often fail or take much longer than they should. The Sense still seems to lose connection with my phone on occasion, which causes some watch faces to stop updating data like the weather. The watch has also rebooted on my wrist a couple of times, which is annoying when you just want to see what time it is. On the plus side, I do feel like notification syncing has gotten more reliable compared to past Fitbit watches, which is very welcome. Managing notifications on the watch is tedious, though, because the interface is pretty sluggish even with Fitbit's improved (and unnamed) CPU.

I was happy to see so many neat watch faces in the Fitbit store, but Fitbit has no payment mechanisms in place. So, developers have to take payments on third-party websites and give you codes to enter on the tiny smartwatch screen. There are a lot of paid watch faces, too. It's just not a great experience.

While the watch's UI can be slow, there are some great quality of life improvements in the new Fitbit OS. The quick settings panel to the left of the watch face lets you control things like always-on mode, sleep mode, do not disturb, and volume. You can also long-press the button to launch an app or feature of your choice, and a double-tap opens still more quick launch shortcuts no matter where you are in the UI. The Today interface scrolls down below the watch face, and it has more data than it did in the past. Although, it's also very slow to load, and it makes the entire UI lag.

If you're looking for a running companion, the Sense might not be the right watch. There's no option to store music on the watch unless you use Pandora Plus or Deezer, which you probably don't. You can control playback on a phone (if you have it with you), but doing so requires pairing the phone with your watch all over again in "Sense Control" mode. The watch does have GPS for run tracking in the absence of a phone, and it seemed accurate enough in my testing, but I'm not picky about saving my exact route. I have seen numerous complaints about its accuracy from people who are picky.

The watch supports Alexa and Google Assistant, but Assistant isn't available yet. That's just another thing Fitbit says it's addressing in the coming weeks. That does seem to be a pattern with the Sense. It even launched without ECG support, which rolled out while I was working on this review. You also cannot take calls on the watch, but you will be able to "soon."

Exercise tracking is one of the most important features of a fitness-oriented smartwatch, and Fitbit has traditionally been good here. Watches like the Ionic and Versa always tracked my workouts well, but the Sense has some strange issues. The Sense supports detection of seven different workouts, but this feature has not been reliable for me. Each time I set the Sense up on a phone, workout tracking functions for a few days, and then it stops. I'm not sure if this is a widespread bug or an issue with my unit. I'm in contact with Fitbit and will update if they find a solution. You can, of course, manually log workouts from the watch, but workout detection is a must-have feature for me at this price point.

Fitbit claims six days of battery life on the Sense, and that's close to accurate in my testing with always-on display disabled. You'll lose about three days if you leave the display on, but I'm personally willing to do that because I find the feature so useful. The Sense still lasts plenty long, and the charger is fast. A few minutes of charging is enough for a day or two of use. There's no range anxiety with this watch.

Should you buy it?

Fitbit Sense

Probably not, at least not until Fitbit fixes some bugs and makes improvements to the sensors. I'm not getting as much insight into my health with the Sense as I had expected. Part of that is that some of the sensors work in very narrow instances, like the SpO2 sensor that only reads at night with the correct watch face. The bugs with workout tracking are also reducing the amount of data I have in the app. That said, the hardware is attractive and comfortable, and there are some nice improvements in Fitbit OS.

I'm a sucker for an LCARS watch face. This also shows exactly how large the bezels are.

At $329, I expect a polished wearable experience, and that's not what you get with the Sense. The Sense feels like an unfinished product that is not worthy of the premium price. Meanwhile, the Versa 3 is almost the same watch, minus some of the more esoteric sensors, and it's $100 less. Perhaps in a few months, the Sense will evolve into the watch I was hoping it would be. The Ionic did improve markedly in the first few months following its release, after all. The company has promised to make numerous improvements later this year, and I'll take another look at the device when and if that happens.

Buy it if...

  • You already use a Fitbit device and want to stay in that ecosystem.
  • You trust Fitbit to address bugs and feature gaps.

Don't buy it if...

  • You don't want to spend over $300 on a smartwatch (the Versa 3 is $100 cheaper).
  • Features like ECG and EDA sensors don't matter to you.


Fitbit, Amazon, Best Buy

Big improvements

Fitbit promised a lot of improvements to the Sense in its first major update, and it came through—so, we're bumping the score from 6 to 7. Almost all of the missing features I complained about in the initial review have been added in the v5.1 update, and there are some excellent quality of life improvements. Most importantly, the glaring bugs have been addressed, making the watch vastly more pleasant to use.

The SpO2 sensor is now worth having as you don't need to set a particular watch face before going to bed. Your watch will log blood oxygenation automatically overnight, which you can view in the app or by setting a watch face that displays the data at any time. Setting watch faces still fails on occasion, but it's been more reliable for me on v5.1. I haven't seen any of those bizarre system crashes after the update, and the interface is much less laggy. I wouldn't say it's fast, but it's no longer frustrating to do basic things like check your fitness stats.

This update also added Google Assistant support, and it's surprisingly good. I have it set to activate with a long-press on the solid-state button (which I'm still not crazy about), and it pops up right away even if the watch has been asleep. It supports all the same commands as other Assistant endpoints, and I've only seen it fail once when I was two floors away from the connected phone. Honestly, Assistant on the Sense is better than it is on Wear OS, and that's a little embarrassing for Google. Phone calls via the watch's microphone are also supported now, crossing off another missing feature.

Perhaps my biggest complaint about the Sense at launch was the unreliable workout detection—that seems like something Fitbit should nail. My experience has been markedly better after the update. The watch hasn't missed a workout in the last week, logging them all in the Fitbit app with the correct activities (usually) attached. The times automatically logged aren't as accurate as I'd like, but it's within a few minutes. Maybe if you're really serious about training, you won't dig that. I think Fitbit skews a bit more mainstream, so it's forgivable.

I'm not shocked to be writing a positive update—we've seen this happen before with Fitbit products. In my experience, it seems like Fitbit launches devices before they're ready, but it circles back a month or two later with an update that smooths the rough edges. The same thing happened with the Ionic smartwatch, leading me to post a very positive update several months later. And here we are again. It would have been nice to have all this stuff at launch, but like they say, better late than never.

Sadly, this update won't change the annoying non-button, the new proprietary band connector (I believe the third design in three years), or the high price tag. I still don't think the Sense is worth $330, but it's getting there. If you want all the sensors Fitbit offers in the Sense, I think you'll be satisfied with the experience. Otherwise, get the Versa 3, which is running the same improved software and costs less.