Comparison of Fitbit Flex, Fitbit Charge HR and Fitbit Surge

Fitbit is considered to be the world’s largest manufacturer of “health gadgets”. In the US, for instance, Fitbit fitness trackers’ share of the fitness bands market is exactly 50%, which is very prestigious since it is the USA which is the leader of wearable devices sales.

The story of wearable fitness trackers began 7 years ago, in the autumn of 2008 when Fitbit first launched Fitbit Classic. This ancestor of modern trackers already had a built-in accelerometer, kept daily track of burnt calories and monitored the users’ sleep quality. Within 7 years which passed from the release of Fitbit Classic, the company managed to introduce several best selling devices.

Which Fitbit band is the coolest one? We’ll reveal the truth to you. This will be a long and detailed review, so make sure you’re comfortable and have some time on your hands.

Which Fitbit fitness band should you pick?

Before we carefully analyze each model, let’s take a look at the main facts concerning the products featured in our review: how they are positioned by the manufacturer and how much do Fitbit Flex, Fitbit Charge HR and Fitbit Surge cost.

Let’s start with a classic wearable device, Fitbit Flex fitness band. Flex is sold since 2013 and became one of the most popular trackers of that year alongside with Nike Fuelband and Jawbone UP. This popularity and even legendary status was earned due to various reasons, such as a good battery, simplicity of control and… the cut-rate price, which is quite moderate for the brand-name device.

What is Fitbit Charge HR? Do you remember Fitbit’s flop with the development of “Force”? It is Fitbit Charge HR that became the company’s main attempt to reclaim its good name and its lost market positions. The attempt was successful, by the way. In 2014 the fitness industry giant introduced simultaneously two very similar models: Fitbit Charge and Fitbit Charge HR. The latter had a built-in optical pulse tracker. This option, which was rare at the moment, won the hearts of the healthy lifestyle fans and made the device the market leader. The classic Charge didn’t remain in the shadow of the tuned product and sold well in the lower price segment. Fitbit Charge HR’s.

Fitbit Surge is positioned as a smart watch. Exactly, officially this isn’t a fitness tracker, but a smart watch, as Fitbit’s marketing team positions its latest gadget. By the way, this isn’t the first time that we discuss this smart watch: do you remember our comparative review of Jawbone UP3 vs Fitbit Surge vs Basis Peak?

Surge was launched on the market right after Charge and the difference between the two was that the former’s screen was considerably larger and was equipped with some new advanced options. We’ll discuss the functionality of Fitbit Surge below, and right now we’ll only note the obvious fact that Surge looks like and costs like an elite gadget.

Fitbit Flex design and ergonomics

Fitbit Flex’s style is most minimalistic. Both the main advantages and disadvantages of this model are connected with this minimalism. Here it is, Flex – a mere silicon band on your arm with a bunch of The Core sensors inside it. It is discreet and suits any style, be it a sporty style or a classic one. Far from all models of fitness trackers can blend in such an insensible manner: Surge, for example, is a typical sports gadget and it would look strange if you wear an expensive tux or an evening dress with it.

Fitbit Flex fitness tracker

Flex is modest and isn’t supposed to demonstrate that its owner is well-off. It is made of hypoallergenic materials, suits well both smaller and larger arms, doesn’t leave any wrist blisters. At first, everything seems to be excellent! But all customers complain of the cracks which cover the tracker’s band. The folding spots burst regularly! Here’s a typical review of Fitbit Flex: “In a couple of weeks after purchase, different spots on the band began to burst. The only good thing is that these bands are cheap and easy to buy”.

Fitbit Charge HR: design and ergonomics

Charge is a wider Flex, or a narrower Surge. Long story short, it is a middle ground. It’s got a tiny one-line OLED screen for viewing real time statistics. Charge shows the main data without any faults. You have to agree that this is more advanced than Fitbit Flex LED system (two lights are lit when you didn’t walk enough; four lights are lit when you’ve had an excellent walk).

The band and the body of the tracker are also made of silicon. Charge HR comes in different colours: black, burgundy, blue and orange.

Fitbit Charge is water-resistant but is not waterproof, which means that you can train wearing this band and wash your hands after that but you’d better take the tracker off before taking a swim in the swimming pool or sea.

Flex comes in three sizes instead of two. The majority of feedback online is positive. We have been able to find only a couple remarks on the comfort of this band:

“The sensor presses against the arm and leaves a trace after long wearing (which comes off quite soon). This is not critical for me, I simply change the band’s position on my arm two or three times a day (I move it an inch higher or lower). I had no allergies or any other consequences”, – states Old_user.

“This band is not waterproof, so I’ll take a point off for that. I’m wearing a Sony tracker at the moment and I have already forgotten what it’s like to protect wearable devices from water. Taking off and washing the band with soap and then rinsing it after a training would be just fine”, – as criticizes the device the user CR17.

And he is right: the level of water resistance could have been higher for $150. This type of criticism is absolutely relevant.

We don’t recommend you to wear Charge HR while swimming, special fitness trackers which we covered in the review of the best fitness trackers for swimmers will do better.

What does the Fitbit Surge look like?

It looks cool! Surge is a smart watch which gravitates towards sports style. A screen of considerable dimensions makes it look bulky and even heavy, however, hence the benefits.

Fitbit Surge smart watch

This model has got an LCD screen with diode backlighting. The screen is sensor which means that when operating the device you can do without taps which are typical of Flex and Charge, although the taps are the most convenient form of contact when running as it won’t be easy to hit the right spot on the run.

The band of the tracker is made of silicon and is available in black, orange or blue colours. Surge has got the highest level of water-resistant out of the whole range of Fitbit devices: up to 5 atm. In reality, though, the device can break down even if it is hit by a slight rain (according to the Fitbit Surge users’ reviews).

The competitive edge of this model is that it truly looks expensive. Fitbit’s designers have worked really hard: the body is chrome plated, the clasp is metal and the screen is of high contrast. But is everything so perfect? Unfortunately, we’ve found quite a few complaints from those who bought Surge:

“The band is really thick, it is about 3 cm wide, and even though the rubber is soft to touch, a single drop of sweat during the training session will make you want to take the tracker off. The rubber from which the band is made is ribbed so any dust is perfectly visible. Given the fact that you can’t wash this band, this becomes an issue. I believe it’s too bulky for everyday wear.”

Perhaps none of these flops would be noticeable if it wasn’t for the price of the device. You can’t deny that the gadget which is worth $250 should be striving for perfection when it comes to convenient and comfortable use.

The comparison of functions and characteristics of Fitbit Flex, Fitbit Charge HR and Fitbit Surge

It becomes immediately obvious that the logic of assessment of functionality and characteristics is typical: the younger the product is, the more advanced it is. That’s why we’ll leave the most tuned (and most expensive) Fitbit Surge for later and we’ll start with more outdated Flex and Charge.

Fitbit Flex review

The main problem of Flex is that it becomes more and more obsolete with each month. Once this tracker used to be on the forefront of high-tech, and today the snobs of high-tech condescend to it: you won’t surprise anyone with the step counter or sleep analyzer… Even the benefit of low price is barely legit: other trackers, which are not inferior to Fitbit, have long been launched on the market.

On the other hand, Flex is a very robust product. It doesn’t have any frills, but it does well the things it can do. It is ahead of most of the modern fitness trackers in terms of quality of step counting, for example. This means we won’t write off Flex just yet.

  • We have already mentioned the altimeter and the step counter: the experts and regular users note the accuracy of these functions of the tracker
  • The sleep analyzer is also advanced; just like most of the modern fitness trackers, Flex differentiates between the deep and the light sleep and can serve as an alarm clock.
  • The band can also calculate the amount of calories burnt during the day, it keeps a record of consumption as well. The pickiest consumers claim that Fitbit Flex cannot be called the most precise gadget when it comes to these aspects.

Fitbit Flex is very democratic in terms of compatibility: it is compatible with Windows Phone, Android and iOs. Connection to PC via Bluetooth works flawlessly as well. Each tab shows your daily performance: how much you have walked (both in steps and kilometers), how much you’ve run, how many calories you’ve burnt and how well you’ve slept.

Fitbit Charge HR review

When it comes to Charge, add a PurePulse technology optical heart rate monitor to your typical step counter and sleep analyzer. This technology makes it possible to constantly monitor the pulse while conserving the battery. This results in the improvement of physical activity tracking, and in more accurate record of burnt calories and heart health analysis.

Fitbit charge HR activity tracker

Charge HR classifies your heart rate in one of the three so-called “zones”: the zone of regular, low and high pulse. These zones can be adjusted by the user taking into account personal health peculiarities. The gadget assesses which zone your heartbeat fits during the training, walks and even during sleep. The device outputs recommendations so as to cut or increase the exercise stress according to the collected data.

Although this sounds impressive, many customers complain of malfunctions of the Fitbit heart rate monitor.

Just like with any other step counter, you’ll have to set up the software on your iOs or Android or in your browser (USB Dongle which is supplied with the device is used for PC). When you’ll be running the app for the first time, you’ll have to list your gender, weight, height and other personal data. By the way, the developers bothered to work on the social functions of the gadgets and oon motivating the users: you’ll find competition for yourself; you’ll be able to control your goal setting, and online ratings of the healthiest users. Long story short, you definitely won’t be bored with Charge!

The beginnings of smart watch can also be found in Fitbit Charge. It can show the time, for example, notify the user of the missed calls on the cell phone, use the GPS module of other devices and even read the bar code! You can get all these perks for just $150.

Fitbit Surge review

Here we no longer find the beginnings but a complete functionality of a real smart watch! With the help of this watch you’ll even be able to control the playlist on your smart phone or tablet during a training session.

The true fans of running will appreciate the built-in GPS module which gives the users an opportunity to analyze its activity both in marathon and sprinter modes. The only drawback of this innovation is that the satellite positioning considerably affects the battery and decreases the running time substantially.

The main functions are identical to those of Charge. Here an altimeter with the step counter, an ongoing heart rate monitor and an advanced analyzer of physical activity can be found. Yet once again we see claims regarding the quality of these sensors. The gadget is said to monitor the heart rate poorly and the altimeter is said to lag at any given opportunity.

The software here is really advanced though. First of all, the smart watch is compatible with all popular mobile operating systems. Second of all, the gadget’s analyzers deserve recognition. The gadget can identify running, cycling, walking and even practicing yoga! Being worth Fitbit Surge has got relevant software of which Fitbit Flex couldn’t dream.

Running tracking visualization on the city maps is accessible on any smart phone or tablet and looks impressive as well. You’ll feel like a true athlete when you’ll take a look at the red circles on the map of the city park after your running session.

Fitbit Surge has also got the Treadmill Run. The distance is measured in steps exclusively. In order to enhance the accuracy of the Fitbit step counter, you can additionally adjust the length of a step in the settings.

different colours of fitbit surge

As for the details, we’ll draw your attention to voice recognition and, of course, sensor gadget control. To our regret, Fitbit Surge does not support data export, which is a serious disadvantage for pro athletes. The developers seem to have promised to support Strava, but this promise hasn’t been fulfilled yet…

The feedback on Fitbit bands

You can say what you like, but Fitbit devices always guarantee a certain level of quality. It is not in vain that all three models described in this review are consistently rated high by the customers. The average rating is 4 stars out of 5.

But still, Fitbit Charge HR is still the public’s favourite. It is this gadget that is most loved by the customers, although some of them do criticize it.

“The pros of this model are: constant pulse tracking, pulse tracking during running is the key function for me and it works well. The chilliest thing is that you don’t have to press the button while running; all you have to do is double-tap the band to view the info you need. The calories and step count works pretty much like in other trackers. My wife loved the quiet alarm clock as she gets up later than I do”, – commented MadKev.

Those rare complaints that we come across are usually devoted to poor water-resistance and special bugs and flaws. The users of Fitbit Charge HR will give you the details themselves, as there are over 3 thousand comments to this device.

The heaped Fitbit Surge gets most criticism actually. Apparently the customers are not satisfied with not getting value for money. In any case, this band’s rating is lower than that of Fitbit’s other products.

“The pulse is measured normally only when resting, the device can’t identify which floor I’ve reached when climbing the stairs, it miscounts the steps (adds a thousand when I’m driving), the battery only lasts 3 days while the manufacturer claims that the battery life is 5 days with GPS off” – complains Demian.

The fitness industry senior, Fitbit Flex, has righteously gained respect and honour from the public. Most of the customers agree that it’s worth its price. However, there is a room of criticism in any positive review.

girl with a fitbix flex

“The device counts the steps well. It also recognizes sleep accurately. Unlike Jawbone, the breakdown of the actual band won’t make you throw away the tracker – all you have to do is buy a new band. The software, however, is constantly lagging. Thanks to this band I’ve realized that I only sleep for 6 hours a day instead of the necessary 8 hours, so normalizing my sleep pattern turned out to be a big deal!” – explains Expert.


Fitbit fitness gadgets line is a worthy example of “health bands” which are aimed at regular users rather than pro athletes.

Fitbit is always at the forefront of the high-tech development and guarantees the brand name quality to the consumers. Our review proved that even the three years old products of Fitbit remain up-to-date and are quite popular. Fitbit Surge, the new model, is also in the general trend of integration of smart watches and health bands.

Nevertheless, we believe that the happy mean out of these three gadgets is Fitbit Charge . Its good value for money, up-to-date software, the heart rate monitor and high level of customer trust make it currently the best Fitbit gadget.

Nevertheless, the other models are well sold nowadays too. If you are conservative or if you are beginning a healthy lifestyle, Fitbit Flex will suit you, and the fans of sporty style and expensive devices will love Fitbit Surge .

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