Fitbit Flex 2 review

Fitbit has updated its original activity tracker wristband, the Fitbit Flex, with the Fitbit Flex 2 – keeping the minimalist design and five-LED display, but adding a wide-range of fashionable accessories and holders, and even making it the company's first waterproof fitness tracker. It's also the first to count your swimming laps and is sure to be a hit with Fitbit users who want to add swimming to their exercise stats. See also: Best activity trackers

To see the full range of Fitbit activity trackers see Which Fitbit is best?

Note: We have had limited hands-on time with the Flex 2, and will update this review when we have spent more time testing it.

Fitbit Flex 2: New features

At a glance:

  • Swim-proof, counts laps
  • Interchangeable bands
  • New accessories including pendant
  • Reminders to move
  • Automatically tracks certain exercises
  • Call and text notifications

Fitbit Flex 2 review: price

The Fitbit Flex 2 costs £79.99 (US$99.95; €99.95). That's the price for the wristband and tracker. If you think this is expensive, compare it to the cost of gym membership or a decent pair of running shoes. I actually saved the price of my tracker over a couple of months of walking rather than catching the bus or tube home.

You don't have to wear the Flex 2 as a wristband. There are bangle and pendant accessories to to hold the removable tracker. If you want the bangle or pendant holder for the Flex 2, you'll have to buy them separately. The Silver Bangle or Pendant is slightly cheaper at £69.99, compared to the Gold Bangles (Gold or Rose Gold) or Pendant's £79.99 price tag. Sadly it's not possible to buy just the bangle or pendant with the tracker; the wristband must be purchased to get your hands on the tracker.

Fitbit Flex 2 hands-on review

The Fitbit Alta, with its larger, more informative screen costs more at £129.99 (US$149.95; €149.95), and the heart-rate monitoring Fitbit Charge 2 costs £129.99 (US$149.95; €159.95). 

Fitbit Flex 2 removable tracker

Keeping fit and using computers didn’t used to go together. Sitting in front of a screen for hours doesn’t burn calories or do anything for your posture. That was before we could carry our computers around with us, and even exercise with them. There are plenty of running and exercise apps for the iPhone and Android smartphones that will work out how you’re doing while you work out. The evolution of wearable computing and activity trackers puts tech at the heart of the modern keep fit fanatic. Stats, alerts, prompts and more stats make even boring exercise fun.

Today's activity trackers are an even better way to push yourself to exercise more without having to pretend to yourself that you need a gym membership – and they're a great deal cheaper, too. Light exercise such as walking can quickly improve your fitness and health. It doesn't have to be leotards, dumbbells and marathons. Trackers like the Fitbit Flex 2 keep you on top of how much you increase your exercise and even allow you to challenge yourself against friends and family.

Fitbit Flex 2: features

Fitbit Flex 2 hands-on review

Using its MEMS 3-axis accelerometer the Fitbit Flex 2 tracks Steps, Distance, Calories Burned, Active Minutes and Hourly Activity, Swimming, plus Sleep Duration and Quality. It lacks the altimeter present in the Fitbit Charge 2, Blaze and Surge, so doesn't measure Floors Climbed.

It also misses out on the more serious multi-sport functions boasted by the Charge 2, Blaze and Surge. This is the reason it doesn't feature the heart-rate monitor found in those other Fitbit trackers. It beats them all at swimming, however.

When you get calls and texts Flex 2 vibrates and the LED display flashes its colour-coded lights discreetly. Without a proper screen, the Flex 2 doesn't show Caller ID when the user's phone rings as the Fitbits with larger displays do. So the Flex 2 offers the major activity tracking functions but not all the sports stuf and smartphone bells and whistles.

The Flex 2 will alert you when you're inactive for too long during the day via its Reminders To Move alerts, which are activated if you miss the 250-step an hour minimums. This can be switched off, but is a great way to get you out of your chair to walk around and stretch your legs and get moving.

Fitbit Flex 2 review: the only waterproof Fitbit

It is, however, the only Fitbit tracker that is fully waterproof and boasts the ability to track swimming as an exercise.You have to enter the length of your pool in order to accurately count laps, and this is done via the Fitbit app. We're told that it works with front crawl (freestyle), backstroke, breaststroke and butterfly.

You can wear it in the shower or bath, unlike the other only water-resistant tarckers from Fitbit. Also, see our round-up of the best waterproof swim trackers. We think that the Flex 2 might even be used by some Fitbit enthusiasts as a second tracker speciifically for the pool.

The Flex 2 is Fitbit's first properly waterproof fitness tracker, and can track your swimming as an exercise activity. We haven't fully tested the Flex 2 on a rigorous swim, but will update this review when we have. The Flex 2 measures your Swim Duration, and calculates calorie burn during your time in the pool.

Fitbit doesn't recommend extended exposure to water, so don't leave it in a bucket of watewr overnight. Like you would!

In fact, we suspect most of the Fitbits aren't as water sensitive as Fitbit warns. The company took a big PR hit when one of its old wristbands (the wonderful but cursed Force) was blamed for giving some users a nasty wrist rash. Fitbit discontinued the Force, and its replacement, the Charge HR, was a massive success. Bit since the Force the company has been wary of recommending its users keep the wristband on for extended periods of time and certainly not in water.

Yahoo tech columnist David Pogue spoke to a Fitbit product manager who (shhh) admitted that even the Fitbit Charge 2 could be worn in the shower without damage, as long as the shower isn't super-powered. Pogue tried this out and had no problems with his Charge 2. But only the Flex 2 is guaranteed waterproof by Fitbit, and is the only Fitbit to actively track swimming.

Fitbit Flex 2 review: sleep monitor

Why wear the Flex 2 all day and night? Because it monitors not just your activity during the day but how you sleep at night, too. Sleep duration and quality is an important health metric, and one worth as much consideration as physical daytime exertion.

Fitbit Flex 2 wristbands

Fitbit Flex 2 review: accessories

The Flex 2 wristband is available in Black, Lavender, Magenta and Navy. You get both a Small and a Large wristband when you buy the Flex 2.

The Fitbit Flex was one of Fitbit's longest-surviving trackers in its range, and for good reason – it was slim, and so lightweight you forgot you were wearing it. Its update, the Flex 2, is even slimmer and comes with a range of accessories that suggest Fitbit is aiming this tracker at women – or very confidently fashionable men...

You can wear the Fitbit Flex 2 on your wrist in the slim band, in a bangle, or hung from a pendant. This is possible because the actual pebble-like tracker is removable, and be fitted into the three types of holder. You'll need it in the wristband to track your swimming. It can be in the Bangle, Pendant or Wristband for the other dry-land activity tracking as you prefer.

Fitbit Flex 2 bangles

The hand-polished Bangle (pictured above) can be bought in Silver, Gold and Rose Gold colours. The Silver version is £10/$10/€10 cheaper than the Gold versions.

Fitbit Flex 2 pendants

The Pendant (above) is available in either Silver or Gold, on a 17-inch chain. The Silver version is £10/$10/€10 cheaper than the Gold version. There's no Rose Gold version of the Pendant available yet.

Fitbit Flex Sport and Pink packs

Flex 2 owners can also buy two three-packs of wristbands. The Sport pack has bands in Grey, Yellow and Navy. The Pink pack in Magenta, Lavender and Blush Pink.

The new Flex 2 removable tracker is about a third smaller than the original Flex tracker, which has made it possible to slim down the wristband and accessories.

There's just "One Size" but Fitbit includes both a Small and a Large wristband in the box.

The Flex 2 uses a similar pop clasp as the Fitbit Alta, which some have found initially tricky to close. You do get used to it fairly quickly, and adding a more secure watch buckle might spoil the look.

That said, initially the experience can be annoying. Fitbit includes just the one metal clasp, attached to the Small band. If you need the Large band you must first remove the clasp from the Small band (I predict a few broken nails here) and then add it to the Large band (again fiddly and quite frustrating). Fitbit should include a clasp on each band and not save a few pennies at the expense of its customers' patience and nails.

Fitbit Flex 2 removable tracker

Fitbit Flex 2 review: Fitbit display and alternatives

In many ways the Flex 2 is similar to the Fitbit Alta, which is also worth considering as it has largely the same features and some new ones, plus a wider range of accessories.

Where the Alta differs from the Flex 2 is its larger display, which shows you your stats right there on your wrist rather than having to go to the Fitbit app as Flex 2 users have to.

The Flex 2's display is a series of just five simple lights, each representing 20 percent of your daily Steps target. So if your target is 10,000 steps you get a light switched on for every 2,000 steps. A blinking light shows the current segment of the goal you’re working on. When you reach your goal, your Flex will vibrate and flash the LED indicator lights to celebrate. It works really well, and many will prefer this minimalist approach to the larger displays. If you want more info then the Alta is the nearest alternative, but it's slightly larger and more expensive.

Fitbit Flex 2 vs Fitbit Alta

On the Alta and other Fitbit tracker wristbands the display shows the actual statistics in numbers, plus a watch face to tell you the time, and Caller ID linked to your smartphone. Flex 2 users won't be bothered about missing the immediacy of such data, preferring to keep their fitness band as minimal as possible. If you want your stats numbers visible on your wrist then the Flex 2 isn't for you. It can, of course, be worn with a watch. 

And don't forget that the Alta is not waterproof, and so can't be used to track your swimming exercise. As mentioned earlier, maybe the Flex 2 will be used by some as a second swim-only tracker – Fitbit allows multiple trackers to be tied to one person's account.

We also like the Fitbit One, which is a little gadget that clips onto your belt or bra, or can be carried in a pocket. A potential pain with non-wristband trackers is that they are quite easy to lose, with the usual knocks and scrapes a body can get itself involved in during the average day. I lost mine at a children’s party – not an average day (thanks goodness!), but regular enough to pose a risk of loss for the tiny gadget.

Fitness wristbands such as the Fitbit Flex 2 remove this risk by being more firmly attached to the body and easier to monitor that it’s still in place. The Flex 2's bangle and pendant options also make it stand out among the many activity trackers available today.

Wearing a fitness wristband is just like wearing a watch. After a few minutes you forget you’re wearing it at all. They’re light, and most are stylish enough for hip keep fit fans to show off. The Flex 2 is smart but it's not a watch, as the display shows just dots not figures.

Top 10 tips for hitting your Fitbit step goals

More: Fitbit One review     Fitbit Zip review    Fitbit Alta review     Fitbit Charge 2 review     Fitbit Charge HR review   Fitbit Blaze Review     Fitbit Surge review

Fitbit Flex 2 waterproof and swimming

Fitbit Flex 2 review: seeing your stats and data

As the Flex 2 lacks a large display you need to go to the mobile Fitbit app (iOS and Android) or the more expannsive Fitbit desktop dashboard to see the actual numbers, as well as some lovely graphs showing your fitness and health trends.

Fitbit Flex 2 review: goals and badges

You set goals for each of the measurements, and can earn badges for goals achieved. The Flex 2 also gives you a gentle vibrating buzz on the wrist when you hit your Step goals.

The calculation of steps taken is never going to be 100 percent accurate but the distance isn’t way off in our tests. The thing to remember is that the measurements are relative. You’ll soon get an idea what you get up to in an average day, and you set out to beat that average and walk or run more, climb stairs rather than take the lift, leave the car in the driveway or walk past that bus stop.

You can input your weight every day but this isn’t compulsory so don’t let that put you off. You might also be interested in Fitbit's Aria scales that sync with your account, and measure weight, body fat percentage and BMI; read our Fitbit Aria scales review. There are plenty of other digital scales available; check out our round up of the best digital smart bathroom scales.

Fitbit Flex 2 review: monitoring sleep

The Flex 2 automatically recognises when you are asleep and when you wake. It tracks both the number of hours slept and the quality of that sleep (eg. restlessness).

Helpfully, the Flex has a silent wake alarm that gently vibrates to wake you at your desired time, without disturbing anyone else. You set alarms using your computer or mobile device. Silent Alarms can be configured to recur every day, or on particular days of the week.

Fitbit: compete with friends

While setting yourself goals is a good push to keep up your motivation there’s nothing like a little competition, and Fitbit allows you to track your exercise against other Fitbit-wearing friends. There’s a leaderboard on the website and on the app. This is the fun part of amassing steps, and can get  quaite competitive. Of course you don not need to compete against others if you prefer your exercise to be private.

Fitbit sends out a weekly email of your stats so you can easily keep up on your progress. It will also compare your stats with the people you are competing with. If you want to keep any stats secret you can use the privacy settings on the website.

Fitbit Flex: battery life

The Flex 2 should last about five days before needing a charge. Try to remember to keep it charged as it’s frustrating when you’re just about to walk or run and the battery fades out. The best time to give it a charge is while you’re asleep (although you'll miss that night's Sleep monitoring) or sat stuck in the office, or maybe relaxing in front of the TV or reading a book.

Fitbit Flex 2 accessories

Fitbit Flex 2: Specs

  • Tracks steps, distance, calories burned, active minutes, hourly activity and stationary time, plus sleep quality.
  • Tracks steps, distance, calories burned, active minutes, hourly activity and stationary time, plus sleep quality.


The Fitbit Flex 2 is a chic and slim, lightweight wristband (with bangle and pendant accessories) that tracks and monitors your daily activity and sleep patterns. You can compete with Fitbit-using friends. The Fitbit Flex 2 will give you added motivation to walk or run that bit further, and keep an eye on your weight and fitness activities. If you prefer more stats right there on your wrist consider the Fitbit trackers with larger displays. It’s addictive and fun, and has the most accessories of any Fitbit – making it, of course, the most flexible Fitbit ever.

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