Fitbit Flex review: A most versatile, feature-packed tracker

The $99.95 Fitbit Flex is the newest personal fitness tracker in the company’s lineup. While the Flex isn’t without some flaws, the gadget is the most complete product of its kind you can buy. It can track steps taken, sleep quality, and it syncs data wirelessly with PCs and Macs automatically. Comfortable to wear, the Flex can communicate directly with iPhones and select Android smartphones, and is water-resistant as well. Going head-to-head with other wristband-style exercise products such as the Nike FuelBand  and Jawbone Up , the Flex offers more features and convenience at a lower price than those more expensive devices.

Fitbit Flex Wireless Activity + Sleep Wristband, Black


Make fitness a lifestyle with Fitbit Flex

Made by: Fitbit, Available: In stock


When I first picked up the new Fitbit Flex, I initially considered its unadorned surface and clean, ring shape spartan. After all, the device lacks a real screen capable of displaying alphanumeric characters. Instead the Flex sports a thin sliver of a display cut from smoky dark plastic. Underneath the plastic sits a row of five tiny, white LEDs that blink to indicate the Flex’s status.

The Flex’s flexible rubbery band, however, masks the product’s true complexity. Inside a small pouch on the strap’s underbelly you’ll find the real brains of the operation, a smooth plastic pebble that contains all the Flex’s electronics. In fact, the LEDs visible from the band’s surface are actually located on this little gizmo. Indeed, half the size of the current Fitbit One and Fitbit Zip, the new Flex is Fitbit’s smallest tracker yet.

Other than its LEDs and a Fitbit logo, the only other features you’ll find on the tracker is a line of metal contacts. These are used for charging the Flex’s rechargeable battery through the supplied USB cable and socket adapter.

Popping the Flex into its band is easy, and the tracker even has an arrow indicating which direction it should be inserted. Attaching the band to my wrist is another situation altogether. The Flex has nine oval holes on one side of its wrist strap, and two hard pegs on the other.To button up the band you snap these pegs into the Flex’s notch-shaped holes. In my experience it’s a tricky process that requires a lot of force. Call me a wimp, but I even injured myself attaching the band; I mashed my thumb too hard against my wrist. Fitbit says that it’s aware of this issue and that it should only affect preproduction units such as mine. One benefit of the Flex’s tight wrist lock is that it’s unlikely to become unhooked.

If you spend a lot of time around water or in the rain, the Flex has your back. The device is fully water-resistant and is designed to shrug off exposure to splashes and short immersions in liquid. As a result I was able to both shower and wash dishes with the Flex strapped to my wrist daily. It’s a good thing, too; the Flex is so light and comfortable, I often forgot it was there. In my opinion, the Flex is more comfortable to wear than the Jawbone Up, another well-designed and highly ergonomic wristband tracker.


Features and performance

The most recent fitness tracker from Fitbit, the Flex offers almost all the same features as the company’s One product. It relies on an internal accelerometer to record the steps you take, the calories you burn. The device calculates this by factoring in your age, height, and weight, which you punch into a linked Fitbit account online.

Another trick the Flex takes from the One is its ability to track the length and quality of your sleep plus how many times you woke during the night. The Flex is much more convenient gadget for sleep tracking, though, since it’s already strapped to your arm. That means you can wear it straight to bed and don’t have to mess with a separate armband like you do with the Fitbit One.

That said, the initiation process for kicking the Flex into sleep mode takes a little practice. You have to tap the device’s screen six times to tell it to start recording your Z’s. Only the right tempo of taps will work — go too fast or too slow and the Flex won’t register your input correctly. By contrast, the big physical button on the Jawbone Up (which also tracks sleep, steps, and calories) is much easier to manipulate.
One upside to the Flex is its LED screen, which displays how far you are towards your daily step goal. Just hit the screen once with your fingertip and the Flex shows your progress on a scale of one to five. When all five lights illuminate you’ve reached the default daily step quota of 10,000 steps. The device will even perform a happy dance when you achieve your goal, complete with haptic buzzing and all lights flashing in a random pattern.

Of course you can tailor your goals to match personal targets, too, but not from within the companion mobile apps (iOS and Android). To tweak your custom settings you need to log on to the Fitbit Web site. The Jawbone Up mobile application allows users to adjust their personal fitness targets for sleep and steps, though it lacks a Web-based UI.

I’ve long believed that the strength of the Fitbit system lies in its powerful online data analysis tools. Both the Fitbit mobile app and Web interface let you sift through your stats in views of days, weeks, months, and a full year. You can also pull from a large food database to log meals and count calorie intake. I especially like the ability to create custom foods, and have often-entered meals stored for fast entry. It makes the tedious task of calorie counting less onerous.

To measure weight in real time, Fitbit’s Aria Body Scale also talks to your Fitbit account and provides concrete data to pit against calories consumed and burned. Also, all of Fitbit’s current trackers, including the Flex ship with Bluetooth adapters to sync collected information wirelessly to PCs and Macs. That’s a trick the Jawbone Up can’t tackle. If you own a Samsung Galaxy S3 or Galaxy Notehandset, the Flex will also communicate directly with the Flex via Bluetooth.

Fitbit says the Flex has a rated battery life of 5 to 7 days depending on usage (i.e., how much you tap the screen). My experience mirrored these claims and was able to last approximately 5 days without needing to recharge. The Jawbone Up, however, has much longer longevity (about 10 days) since it transfers data through a more efficient (but less convenient) 3.5mm headphone jack.

Like the Fitbit One and Fitbit Zip, the Flex seemed very generous when logging my step counts. Many times a week I exceeded by 10,000-step goal by a few thousand. Sure, I live in New York, which can be very hectic, but somehow I don’t think I walk that much.


If you’re in the market for a personal fitness tracker to measure overall activity (plus how well you sleep), the $99.95 Fitbit Flex is an excellent solution. Sure, Fitbit’s own $99.95 One device does have all of the Flex’s core features and throws in stair tracking for good measure. That said, the One’s clip design has a tendency to fall off clothes, or stay clipped to them by accident. It’s also cumbersome to wear around the clock. Wristband-style trackers are much better suited for this type of duty.

That narrows the playing field to the pricey $149 Nike FuelBand and the slightly less expensive $129.99Jawbone Up. While the FuelBand is handsome and sports a real LED screen that can display text (and the time), it only works with iPhones and can’t track sleep. The Jawbone Up, on the other hand, logs sleep and steps, though it lacks a display. The Up also requires a physical connection to sync while the Fuelband uses proprietary (iPhone only) Bluetooth technology. By contrast, the Flex is comfortable to wear and has more features, including Bluetooth syncing (iOS and Android) and access to powerful analytical tools. That adds up to a solid fitness tech buy in my book. Of course, if you’re looking to save a little, the $59.95 Fitbit Zip is also a compelling budget choice.

The Fitbit Flex is a simple way to track steps, sleep, and calories. The Flex’s strap design makes it light and comfortable to wear. It also offers handy Bluetooth syncing, and Fitbit’s platform gives plenty ways to analyze your stats.


Clasping the Fitbit Flex’s strap shut is tricky. Direct syncing is only available with the iPhone, the Samsung GS3, and the Galaxy Note handsets.

Fitbit Flex 2, Black (US Version)
8 Total Score
Start from: $260.00

Fitbit flex 2, black, track steps, distance, calories burned and active minutes. Comes with both small and large size band.

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Product Dimensions

10 x 0.4 x 0.4 inches ; 0.6 ounces

Shipping Weight

5.9 ounces (View shipping rates and policies)

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Currently, item can be shipped only within the U.S. and to APO/FPO addresses. For APO/FPO shipments, please check with the manufacturer regarding warranty and support issues.

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This was my first Fitbit device, and I am very pleased with its performance. I had debated getting the Flex 2 or the Alta, but chose the Flex 2 for its slim profile, waterproof design, and lower price point. I have yet to incur water damage, and the five-light design is very minimalist yet informative.One of the main reasons for purchasing a Fitbit was for the silent alarms, as my alarm would annoy both my roommate and me in the mornings. Although I at first set backup alarms on my phone, I turned them off as I realized the Flex 2 had very strong vibrations that have never failed to wake me up in nearly a month's use.A common complaint is the press-on design of the band, and at first, I was disappointed at how difficult it was to put this on. However, after use, it became much more comfortable to put it on, but not to the point where I felt it was in danger of falling off by itself.Finally, I love the Fitbit software, whether online or on mobile. I like the social aspect, particularly the friendly competitions and challenges. Although this model lacks a heart rate monitor, I use my Samsung Galaxy S7's heart rate sensor in conjunction with my fitbit to track my exercise statistics.PROS:Slim and minimalist designDurable bandWaterproof pebbleStrong, effective vibrations (alarms, notifications)SoftwareCONS:no HR monitor (not truly a con at this price point)I did not receive any compensation for this review. If this review was helpful, please click Yes below! Thank you!
November 27, 2016
I LOVE this band! I had the Fitbit One (clip) for 3 years....its been washed, went swimming, left in dressing rooms, you name it. I'm honestly surprised I didn't lose it sooner. While I loved the simplicity of the One, when I finally lost it the Flex 2 is the same price so I figured I'd try to make the switch.....I was nervous about a wrist tracker from stories about grossly inaccurate step counts. I have a very small wrist and found this to be thinner on my wrist than my Michael Kors watch. It is extremely lightweight, and simple. If you are "gadgety" and want more of a watch function, this won't be it for you. All it does is with 2 quick taps shows your progress on the buttons during the day. It will vibrate with calls and texts, and can remind you to move your 250 steps an hour. It has done a good job with sleep tracking, and I must say is pretty accurate with the step count.Pros:Extremely lightweight, not bulky and the lavender is a gorgeous color.Easy to snap on, and can be worn loose or snug.Water proof-I don't wear it in the shower but put it on right after and don't have to worry about unclipping like my old one when I switch from Pj's to work pants, to workout gear, etc.....Put it on and forget about it (unlike the dressing room I had to go back to 2 hours later after trying on clothes once).Vibrates with texts/calls/reminds you to move every hourEasy syncing/tracking on phone-you can't see anything from the band so you have to sync periodically throughout the day from the app. I have my phone all the time so that's not a big deal for me.Removable tracker pops out easily and can be used in other accessories.Cons:No watch/HR/caller ID functionNo stair climber function-for some reason I really liked that with the One. Kinda bummed.Overall I would say this is an excellent product. Since I have a watch and am not a hardcore workout person, I don't need the extra bells and whistles of other Fitbit models. It does the job, and is holding up nicely. Would recommend.
October 7, 2016
I have never had a fitbit or anything like it, but my friend came to me, one day all excited about her new fitbit, so I decided to get one, that very day. My fitbit flex 2 arrived last night. The fitbit flex comes with 2 decent plastic bands, a small and a large. I chose the small, to wear, which is a pretty good size. I downloaded the app on my I phone 5. I charged the battery and I attempted to sync the fitbit to my phone. The fitbit did not sync immediately, but as soon as I turned my blue tooth off and on, the fitbit synced rather quickly to my phone. I put the fitbit on my wrist. It is quite comfortable, but a little sweaty, once you really start moving. I am an overweight person, and I have not exercised in quite some time. I have to say, I was extremely motivated today, I was excited and determined to go from 0 to 10, 000 steps. I could not believe how happy, I was to see the steps, keep moving upward. I was over the moon, when I reached my goal. The fitbit dashboard on my phone, is amazing, it tells you your steps, food intake, calories burned, sleep activity etc. I am anxious to see my sleep recordings in the morning, over all I am happy with my new toy. Hopefully this will give me the push, I need in 2017 to make some better lifestyle changes. UPDATE-January 13, 2017-My advice give yourself a realistic goal, don't get me wrong, 10,000 steps is achievable, but it is really hard to do, if you are focused and motivated, you can do it, I have personally done over 10,000 steps everyday, in fact, yesterday, I did over 16,000 steps, I use music and I do some stepping in the morning, at night, of course throughout the day.FYI- I love the sleep tracking, it is pretty accurate, it tells you how many times, you wake up, at night, how many times, you are restless, when you went to sleep, when you wake up, I am truly addicted to fitbit.UPDATE-February 25, 2017-I am still doing at least 10,000 steps or more every day. I love the challenges within the fitbit community. There are friend requests and you or other people can challenge each other, to see who can do the most steps, in a day, a weekend, a week. I really love goal day, where each person strives to complete his or her goal. The challenges are really a great motivator for me, to continue to exercise. UPDATE-APRIL 28, 2017-Have had to no problems with my fitbit, still love my fitbit, still using it and still getting 10, 000 steps or more in a day:) no longer a couch potatoUPDATE-JUNE 30.2017-Have had no problems with my fitbit, still love it, I have started to use the food log, which is on the dashboard of the app. The food log is great, you key in what you ate and it automatically pulls up the food and you add it to your log. It is good because it allows me to be more aware of all the food, I have eaten. It also tells me, when I have gone over the amount of food, I am allowed to eat for that, day, according to my weight. I have lost 20 pounds, still loving my fitbit:)UPDATE:SEPTEMBER 11-Fitbit still works great, no problems. I am still addicted to hitting my steps
January 7, 2017
Fitbit Flex review: A most versatile, feature-packed tracker
8 Total Score

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1 Comment
  1. Reply Samantha June 19, 2015 at 10:31 am

    I had the Fitbit and it’s main weakness is the proprietary charger. I’ve had two go out on me already and I’m done with it now.

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