May 27 AT 11:12 AM Sean Riley 6 Comments

Fitbit Flex Review


If you remember, we dedicated a section of our HTC One (M8) review to the Fitbit integration. Our interest was piqued by having that functionality built into the smartphone itself. You can read the review for our full take, but the TL;DR version is that while it is a nice add on for One (M8) owners, it really just left us craving more (and more accurate) data about our daily activities. We used a Fitbit Flex throughout our One (M8) review as our comparison point for the in-built feature and have continued using it since then to get a better feel for what this dedicated device can offer.


Fitbit is the biggest player in fitness trackers with over 2/3 unit share in that market, according to an NPD report released last month. A recent Canalys report claims Fitbits represent half of all wearables. There are numerous other options out there, so to maintain that kind of dominance you know they have to be doing something right. It’s also worth noting that they extended their lead in the market since late last year despite the recall of their flagship band, the Fitbit Force, which took the Flex design and added a small OLED display. There are some merits to the added functionality that the Force brought to bear, and I hope to see it return at some point. But the simplicity of the Flex has its place, as well.

The Good

The virtue of doing one thing and doing it well is espoused in a lot of different areas. I would say that the Fitbit Flex is a perfect embodiment of that principle. The Flex is there to record your steps and your sleep. If you so choose you can set alarms. That’s it, end of story. It won’t be bothering you with notifications. You aren’t going be installing apps on it. You won’t to be talking to it, and it won’t be talking to you. We are accustomed to feature creep adding more and more functionality to our devices. In some cases that is a good thing, but all too often it seems that it’s just adding to the feature list for the sake of a longer list. For an activity tracker, you want something that will reliably track and report your activity and the Flex delivers perfectly on those goals.

Battery Life

fitbit-flex-warningFitbit claims that the Flex will go 5 days on a charge. I reliably hit at least that mark during my time with it. You receive a notification and/or email when the Flex hits 20% life. As long as I plugged the Flex in at some point during the 24 hours that I received that notification, I never had a problem. It takes about 2-3 hours for the Flex to get a full charge, so I typically just let it charge overnight and didn’t lose sleep over the fact that I wasn’t tracking that night’s slumber. While I wouldn’t complain about more battery life out of the Flex, it is enough battery life that I’m not forced to think about it constantly.


The Flex gets a fair amount done with the five simple LEDs available to it. If you double tap the Flex you get a quick update on where you are relative to your goal for the day. It will also throw a little LED and vibration party for you when you hit your daily goal.

When you want to switch into sleep tracking mode, you repeatedly tap the Flex for a couple seconds and it responds by vibrating and displaying two dimming lights. Returning to normal tracking just requires tapping for another couple seconds which will greet you with all five LEDs flashing and a spinning light pattern.

Finally the LEDs display your charging status in 20% intervals when you have it plugged in.


Like the Flex itself, the Fitbit app is fairly spartan. It displays your steps, miles, calories burned, “very active minutes,” current weight, sleep logged, food plan/log and water consumption. You are also able to set alarms with the app, which is a nice way to wake yourself up or alert yourself without disturbing anyone else. The pairing process through the app was quite simple. Once paired I never had an issue with losing connectivity for more than 15-20 minutes. The device keeps tracking regardless of your connectivity, so minor loss of connectivity isn’t an issue.

You can “compete” with your Fitbit owning friends via the app, as well, if you either connect it to your Facebook account or send friend invites out by email. While the numbers alone are an excellent motivator, the added pressure of others seeing your progress can be a big boost.


The Flex retails for $99.95 and can be found just slightly cheaper on Amazon. Many of the other wireless syncing fitness bands are between $130-$200. While these are all certainly luxury gadgets, the Fitbit Flex gets you into the segment about as inexpensively as possible without sacrificing on any critical functionality. While fitness trackers are designed with a single user in mind, the Fitbit Flex comes with both a large and small band should you decide to let someone else take your Fitbit for a spin.

The Not-So-Good

Proprietary Chargerfitbit-charger

The band of the Fitbit Flex is merely the housing for the brains behind the tracker. The tracker itself is just a tiny black device with the aforementioned LEDs, charging contacts and an arrow to help you orient it when putting it in the band or charger. Most wearables at this point do rely on some kind of proprietary charger. In many cases it is both a size and a water proofing issue. Again this hardly sets it apart, and the trade off makes it worth it. But I inevitably lose or misplace these chargers, and at that point I have to at least briefly curse the heavens.

No screen

Yes, I’m being the contrarian here. But I did at times find the lack of a screen–at least to just display the time–to be a bit off-putting. This is possibly a hazard of my role as the “wearables guy” around here; I have grown accustomed to having a device on my wrist. To date that has always meant a screen, so I reflexively glance at my wrist for the time only to find a solid band or at most a flashing LED. This is really a question of what you want out of your wearable. If that is something that just stays out of your way and tracks your activity, then see the “Simplicity” section above.


My wearables experience prior to the Fitbit Flex had been mostly with smartwatches and Glass, so I wasn’t sure how I would feel about a simple fitness band. The concept won me over in just a few days. After a few weeks of use I could really see it changing some of my habits. This was all with extremely minimal setup or maintenance, which is critical if you often find yourself too busy to really concentrate on keeping active.

The lack of a screen with even modest functionality, like notifications or the time, is a bit of a frustration for me. But as I said previously, I know there are people who will appreciate that the Flex isn’t another screen to look at.

Overall I found the Flex easy to use. Ultimately it encouraged me to make healthier decisions everyday with minimal intervention. You can slap a lot of extra bells and whistles on to the experience, but they aren’t necessarily going to get you to your goals any faster and may actually discourage you by complicating the device. With the Flex going for under $100 and offering a feature set that is competitive with the other bands out there, it isn’t a surprise to me that Fitbit is owning this market right now.

Sean has been with Android and Me for over 8 years and covering mobile for the last 9. He occasionally muses about gadgets and tech outside of the Android universe at Techgasms.

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  • Don

    I bought the fitbit flex because they had just pulled the force. Although I was happy and credit it with my weight loss of 30 pounds in just 4 months (kept me focused, without I would not have lost the weight) I found the need to upgrade to the fitbit one. The ONE has all the features of the force but it’s on a clip not Bracelet. Accuracy on the ONE is better due to its altimeter and acceleratomtor. The flex only has a acceleratomtor. For the extra $20.00 or so I would go with the Fitbit ONE

  • Don

    Oh, I forgot to mention that the fitbit One has a screen.

  • Sean Riley

    Thanks for the feedback Don and I should have addressed the One. I personally am not a fan of the clip form, but absolutely if that is a better option for you that is an excellent option and does correct a couple of my minor complaints about the Flex.

  • c1liu

    Nice review, I own the Flex and would have to agree that the charger is a major con. It has annoying connectivity issues. Basically it will intermittently stop charging if it isn’t at the perfect angle, and then you will have to tap it or turn it or hold it to make it start charging again. This annoying tinkering could go on for an indefinite period of time (I’ve sat at the computer messing with it for 5-10 min just to get it to stay in the charging mode). Also, I know at least 2 or 3 other people with the same issue. One of them started using a rubber band to wrap it tighter and said that helped. Other than that it works pretty well, and tracks steps pretty accurately.

  • aranea

    I got one recently and I do like it a lot. I feel like I force myself to move instead of sitting or standing when I can for example while on the phone. Thanks for the tip on turning the sleep mode on. I was using my phone before.

    I got two complaints though.
    1) I wish it let me know when the battery was getting low. Something like two LEDs flashing once in awhile would have been nice. I miss it on the screen sometimes.
    2) I noticed is that it doesn’t sync to your phone if the phone doesn’t have internet connection. So you can’t view number of your steps when hiking in the wilderness. Not a major problem but why not.

  • Rita Barry

    I had no problems with my fitbit Flex for the first week. I have had nothing but problems with it since. It keeps saying that is can’t locate it, when I try to find out how many steps I took in a day. Also for some reason it doesn’t always record my sleep. I have had it since the first of May and I’m about ready to give up on it. I like things simple and simple to use. I thought this would be easy to use and not complicated but I have found out different. I would not recommend it to a friend or anyone else.