Remembering the Fitbit Flex: The tracker that changed how we wore wearables

A nostalgic look back at the budget fitness tracker
Wareable is reader-powered. If you click through using links on the site, we may earn an affiliate commission. Learn more

The Fitbit Flex was a step backwards, for all intents and purposes. It arrived with an ugly rubbery band, provided less accurate step tracking than its clip-on predecessors, didn’t really have a proper display and was bereft of the altimeter admired by owners of the Fitbit One and Ultra wearables.

Yet, it’s the most important wearable in Fitbit’s history. It set the precedent for the company’s long-term home; not clipped to the pockets, but strapped to the wrists of millions. That first true wearable provided a platform for the company to iterate, innovate and eventually become the generic term for Fitbits… sorry, fitness trackers.

Choose the best: Fitbit's latest trackers and smartwatches reviewed

Launched in January 2013, Flex was Fitbit’s original wrist-based tracker. Aside from auxiliary armbands enabling the detachable ‘bit’ to be worn during sleep, all of the earlier models were designed to be affixed to clothing, but the change was probably a necessity. The Jawbone UP was making a serious play for wrists, alongside the mighty Nike FuelBand.

Wristy business

Remembering the Fitbit Flex: The tracker that changed how we wore wearables

There were pros and cons to building for the wrist. On the plus side, the Flex negated the constant fear of losing clip-on predecessors like the One or Ultra. It also kept the company’s smallest ever sensor (it was half the size of the Fitbit One) safe within a rubbery band offering a secure-if-finnicky clip. The whole package was water resistant (not swim-proof), while sleep tracking – which still had to be manually enabled at this point – became more feasible with the tracker affixed to the body at all times.

The band itself was an ugly duckling (one reviewer cruelly described it as a locker key bracelet you’d wear in the pool), but a range of coloured straps enabled wearers to customize depending on their outfit. Third-party fashion brands bought in too, essentially creating a giant new sub-industry alongside the trackers.

However, the new body position brought a significant trade-off and drop-off in step-tracking accuracy. Clipping earlier devices to pockets gave Fitbit a better shot of registering actual steps. However, on the wrist, erroneous arm swings contributed to inflated counts, and those clutching bag straps while walking may have conned wearers out of some steps. Fitbit largely offset this with its cadence algorithms, but it wasn’t quite the same.

The new body position brought a significant trade-off and drop-off in step-tracking accuracy

Crucially though, reviewers still deemed step counts more accurate than the rival Jawbone UP.

With the Flex, Fitbit also ditched the display, which had appeared on all of its trackers to date, and had enabled wearers to keep track of their steps without checking an app or syncing to a PC. Instead, the company deployed a strip of five LED lights, which wearers could double-tap the band to see modular progression towards a step goal.

Again, it was still superior to the original Yves Behar-designed Jawbone UP. The rival device offered a more stylish and truly wearable band, but still required manual (and physical) syncing to a PC to view step status.

A tracker is only as good as its app

Remembering the Fitbit Flex: The tracker that changed how we wore wearables

The Fitbit Flex now offered wireless Bluetooth syncing to the highest-end phones Android and iPhones via the mobile app, something the wearable industry hasn’t looked back from since.

The Fitbit mobile app, even then, was a major strength. It allowed users to log food intake for a side-by-side view of their calorie intake and expenditure, progress towards water consumption goals, active minutes set against a daily average, as well as floors climbed during the day. It offered the ability to log weight and track it over time against increased or decreased activity. It connected you with Fitbit-owning friends and turned it into a competition.

‘Flex saw its users’ getting hooked on hitting the now famous “10,000 steps” daily target, while allowing users to share their scores via social media,” says Ben Wood of CCS Insight. “It prompted a frenzy of bragging posts about the number of steps achieved. The ability to share and compare steps with friends also engendered some fierce rivalry.”

These were the building blocks upon which most tracking apps are still based. Over time, as the technology has improved, and the data has become more accurate and farther reaching, but the general principal remains the same. It was Fitbit that pioneered the way a tracker/app combo could place multiple data points in front of users and allow them to join the dots and draw insightful conclusions.

On the flip side, Ben Wood argues, “the Flex was often seen on the wrist of people who probably least needed it. People who were already relatively fit and could easily hit the 10,000 steps target. It also became a magnet for the “worried well” – people who were concerned about their health and fitness and wanted something that could be used to take data to a GP or to moan about.”

A crack on the Jaw and might of Nike

Remembering the Fitbit Flex: The tracker that changed how we wore wearables

Jawbone notwithstanding, the biggest threat to the Fitbit’s pioneering efforts appeared to be Nike, and while the Flex was cheaper, 2012’s FuelBand was decidedly sexier. It had a display, enabling it to be worn as a watch, and offered coloured lights that showed progression towards goals. In theory it had a much more sophisticated activity tracking system that rewarded movement of all kinds, rather than just running or walking. It also had Nike’s marketing machine (LeBron James and Serena Williams in commercials) and a partnership with Apple that included Tim Cook flaunting one on stage at a keynote.

In the end, FuelBand worked only to Fitbit’s advantage. It raised the mainstream profile of fitness trackers, only for Nike to abandon its hardware ambitions and retreat to the software realm having ignored Android owners until they all bought Fitbits and Jawbones.

Who would have predicted Fitbit would outlast Nike? A fair equivalent might be Pebble ruling the smartphone market today, having seen off the Apple Watch.

How Fitbit flexed

Remembering the Fitbit Flex: The tracker that changed how we wore wearables

Even compared to the sequel Flex 2, the Fitbit Flex looked dated. Now it’s a wearable tech fossil. That original feature set is dwarfed by the bands often given away as freebies with mid-range Chinese phones.

Essential reading: Best budget fitness trackers to buy

However, back in 2013, amidst the 10,000 steps craze, it was a marvel. It got people moving, kept them moving, and often had them jogging on the spot at 11pm to meet their goals. It empowered wearers to make life choices that improved wellness, offered straightforward data presentation and key metrics we could identify all with. And it was a bloody good Holidays stocking filler too.

Today, millions of people including us here at Wareable, who started with the Fitbit Flex 6 years ago, are now delving into more scientific metrics like VO2 Max, power and HRV to quantify our movement and learn more about our bodies. It’s difficult to know whether this would have happened with such speed had it not been for Fitbit’s switch from the pocket to the wrist.

Remembering the Fitbit Flex: The tracker that changed how we wore wearables

Clip-on trackers might have given the company its start, but the Flex was the springboard. Automatic sleep tracking arrived in 2015, making Flex one of the first wearables to get better over time. Full waterproofing, swim tracking, automatic activity recognition, customisable notifications and improved smartphone connectivity followed with the Flex 2. A continuous heart rate monitor tracker, a more attractive design and the return of the display came with the Charge range. Today, alongside a myriad of trackers for all ages and abilities, we have competitive, popular smartwatches with a custom-built OS.

In many ways it’s a giant testament to Fitbit’s relentless iteration and innovation and ability to ride out Godzilla-like incursion of Apple on the market it practically created, to remain as influential and popular as it is today.

Perhaps most importantly, Fitbit continues to do a great job of appealing to everyone in a way that few high-tech companies beyond Apple and Google have.

How we test

Chris Smith


Chris has more than decade of experience writing for the UK's foremost technology publications including TechRadar, T3 and more.

 A freelance journalist based near Miami, Florida, Chris has written for Wareable since its inception in 2014. From reviews of the latest fitness devices, and in-depth features on bleeding-edge wearable devices, to future-gazing interviews with some of the industry's brightest minds, Chris covers the lot. He also writes about sport for The Guardian and is the author of many technology guide books, while also dabbling in film, music, beer, travel and political commentary.

When he's isn't smashing away at the keys of his MacBook, Chris can be found at his favourite craft breweries, dangling his rod in the warm waters of the Florida Keys, or exploring the Shropshire countryside.

You can follow his on Twitter but beware, it's mostly sporting and political hot takes, occasionally interspersed with tech-based tweets.

Related stories