Fitbit currently sells six activity tracker wristbands – the Fitbit Flex, Charge, Alta, Charge HR, Surge, and Blaze – and two clip-on activity trackers: Fitbit Zip and One. Which Fitbit is best for you? Which Fitbit should you get? We explain all in the buying guide to the Fitbit activity trackers. Fitbit trackers compared and features in detail. Also see: Best tech to take on holiday 2016.

There are other activity trackers, of course, so be sure to read the best activity trackers currently available to buy too.

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Which is the best Fitbit: How to choose an activity tracker

Choosing the best Fitbit for you will come down to features and price, but you should also consider size, battery life and of course looks.

For more detailed reviews of each Fitbit activity tracker go to our dedicated review pages, listed below.

Fitbit Charge review     Fitbit One review     Fitbit Zip review     Fitbit Flex review    Fitbit Alta review     Fitbit Charge HR review   Fitbit Blaze Review     Fitbit Surge review

See also: Fitbit vs Apple watch

Which Fitbit is best: price

Let's start with a key factor: cost. None of the Fitbits are pocket change but none are horrendously over-priced either. You'll find cheaper variations online and in supermarkets but there are several advantages to buying a quality tracker. And if you start walking more you can make the money back quite quickly by not taking the bus, tube or train. I saved £100 in around two months, and got fitter into the bargain.

Click on these links below for the latest, best prices from Amazon.

Fitbit Flex - £79.99 / US$99.95 - click here to view today's best prices on Amazon.

Fitbit Charge - £99.99 / US$129.95 - view today’s best prices on Amazon.

Fitbit Alta - £99.99 / US$129.95 - view today’s best prices on Amazon.

Fitbit Charge HR - £119 / US$149.95 - view today’s best prices on Amazon.

Fitbit Blaze - £159 / US$199.95 - view today’s best prices on Amazon.

Fitbit Surge - £199 / US$249.95. - view today’s best prices on Amazon.

If price is important you may be better off trying the clip-on Fitbit Zip or Fitbit One instead. The One costs the same as the Flex, but, as we’ll see, offers more features.

Fitbit One - £79.99 / US$99.95 - view today’s best prices on Amazon.

Fitbit Zip - £49.99 / US$59.95 - view today’s best prices on Amazon.

We think that the £20 ($40) difference between the Charge and the Charge HR might be worth paying for the extra heart-rate-monitoring functionality. But if you're just interested in everyday exercise the Fitbit Charge will suffice, and is an excellent tracker. We also prefer the Charge HR's watch-buckle strap, which feels more secure, and again is worth the £20 ($40) extra. Although Fitbit hasn't announced anything officially, it's expected that the new Alta will eventually replace the Charge.

Remember to factor in the cost of the strap to the price of the new Blaze and Alta if you fancy something different to the included Classic bands. Having a choice of straps is appreciated, but it does make the pricing harder to compare.

You should find cheaper prices at the usual online retailers. Check each individual Fitbit review at the links above for the latest, best prices.

Which Fitbit is best: features

The charts below shows all Fitbit features by device model, plus prices. Click on the image to make it bigger.

Fitbit trackers specs features compared

The cheaper clip-on and wristband Fitbits (Zip and Flex) don’t offer all the features found on the One and Charge, Alta, Charge HR, Blaze and Surge.

All Fitbits have a MEMS 3-axis accelerometer that measures motion patterns to determine your calories burned, distance traveled, and steps taken. All but the Zip also monitor sleep quality.

The One, Flex, Charge, Alta, Charge HR, Blaze and Surge also contain a vibration motor, which allows it to vibrate when alarms are set to go off.

The One, Charge, Charge HR, Blaze and Surge boast an altimeter that measures stairs (or height) climbed. Despite its name the Alta does not include an altimeter.

The Surge boasts eight sensors: 3 axis accelerometers, gyroscope, compass, ambient light sensor, GPS and heart rate. The Blaze lacks the GPS. they track seven days of detailed motion data – minute by minute, and daily totals for past 30 days. They store heart rate data at 1-second intervals during exercise tracking and at 5-second intervals all other times. The Sample rate for GPS is 1Hz.

The Charge HR, Blaze and Surge monitor your heart rate, and without having to lash sensors to your chest like some HR trackers demand. It's all done on the wrist. They use Fitbit's PurePulse heart rate technology that gives continuous, automatic, wrist-based heart rate, plus simplified heart-rate zones.

The Charge, Alta, Charge HR, Blaze and Surge will all show Caller ID when linked to a smartphone. The Surge and Blaze will also display text notifications on its display, and allow you to control your music from the touchscreen display. We found call notifications very useful. You can rely on the wriststrap buzz more than your phone's vibration, and even see who's calling right there on your wrist, which is more polite than and easier than pulling our your phone when chatting to someone else. It's expecially handy when you're at home and your phone is in a different room where you might not hear it.

The top Fitbit wristbands (Alta, Charge HR, Blaze and Surge) feature multi-sport exercise tracking to easily record workouts and see real-time exercise stats and summaries. A recent software update means the Charge HR and Surge can now automatically detect which activity you're doing – and this functionality is also present on the Alta and Blaze. This means these trackers will know when you're cycling, running, hiking or playing sports including football, tennis and basketball. They will also recognise aerobic workouts such as Zumba, cardio-kickboxing and dance workouts. They will record the excercise in the Fitbit app along with an excercise summary.

The Fitbit Alta has a neat new feature borrowed from the Apple Watch. Using short exercise prompts the Alta encourages you to meet a mini-step goal of 250 steps each hour (approximately 2-3 minutes of walking). These prompts can be personalised to your schedule; for example they can be put on “Do Not Disturb” during long meetings or appointments. We love this feature, and hope Fitbit adds it to the other trackers soon. Fitbit says it is working on an update to add this to at least the Blaze.

Fitbit has added Hourly Activity and Stationary Time in the Fitbit app, when paired with Surge, Blaze, Charge HR, Charge, Alta, or Flex, but currently only the Alta actually buzzes you when you fall below that number.

All the Fitbits, except the Zip, check your sleep, too. They measure the time you spend asleep and check the quality of sleep – noting when you are restless or wake up during the night. Increasingly sleep is regarded as a vital health factor. Runing around and eating well won't help you as much if you're sleep patterns are too short or restless. Poor quality sleep is also seen as a factor in heart disease, colds and infections, depression and lack of sex drive.

If losing weight is one of your aims then you should consider the Fitbit Aria, digital scales that wirelessly sync with your account and measure your weight, body fat percentage and BMI. But don't try wearing it on your wrist!

On top of all this the super-fitness-stats Fitbit Surge features GPS tracking, without the need for a smartphone to be linked. Users can see distance, pace and elevation climbed, and review routes and split times. This beats the Apple Watch, which relies on the GPS in your iPhone. The Blaze, like the Apple Watch, requires a connected smartphone, but works not just with the iPhone but Android and Windows Phone too. While built-in GPS is great, most of us exercise with our smartphone on us for music and calls – so connecting to your phone's GPS isn't that much of a nuisance, and saves your trackers' battery.

Here's how Fitbit lists each of the trackers' special features, starting with the Flex:

Fitbit Flex description

The new Fitbit Alta features:

Fitbit Alta features

Now, the Charge features:

Fitbit Charge description

Next, the Charge HR features:

Fitbit Charge HR description

Then, Fitbit Blaze features:

Fitbit Blaze description

And finally the Surge features:

Fitbit Surge description

Top 10 tips for hitting your Fitbit step goals

Fitbit improvements: skin allergies and better clasp

Fitbit was bitten hard when it had to withdraw and recall its Force wristband when some owners reported developing a skin rash as a result of metal allergies. The company now says that it has employed scientific experts Dr Peter Schalock, an Assistant Professor of Dermatology at Harvard Medical School, and Dr Patricia Norris, Assistant Professor of Dermatology at Oregon Health & Science University, to make every effort to reduce the chances of Fitbit users having reactions from parts of their wristbands.

Fitbit still warns that “if you have eczema, allergies, or asthma you may be more likely to experience a skin irritation or allergy from a wearable device.”

It also advices that “if you sweat for more than two hours while wearing your Fitbit band, be sure to wash your band and your wrist using the directions above to avoid skin irritation.”

Each new wristband (except the Alta and Blaze's leather and stainless steel wristbands) is made of a flexible, durable elastomer material similar to that used in many sports watches.

Another problem that beset Force owners was the wristband's weak clasp, which lead to many – me among them – losing their treasured tracker. Now take a look at the back of the Charge HR, and you'll see a surgical-grade stainless steel buckle that's much more like a standard watch. The new buckle is found on the Charge HR, Blaze and Surge, but not the Flex, Alta or Charge. Fitbit has improved the Charge's strap, but it can still come undone and Fitbit acknowledges that it's a problem. It's one of the reasons we recommend the Charge HR instead. Plus the buckle isn't uncomfortable when worn in bed.

Charge HR Fitbit back clasp photo

Which Fitbit is best: display

The Zip display has five modes: Steps; Distance; Calories burned; Fitbit Smiley (highlights your recent activity level); and Clock.

Fitbit Zip display modes

The One’s display has six modes: Steps; Distance; Calories burned; Floors climbed; Flower (grows and shrinks based on your recent activity); and Clock.

Fitbit One display modes

The Flex’s display is the most minimal, consisting of a series of flashing dots that show you how your day is stacking up against your goals. Each light represents 20 percent of your goal. You just tap the display twice to see your progress against your daily goal. This is very easy to get used to but isn’t as informative as the other Fitbits. Of course you can see all your stats via the Fitbit iPhone or Android smartphone app.

Fitbit Flex display modes

The Fitbit Alta takes a longer, vertical view of its displays.

Fitbit Alta displays

The Charge's OLED display (below) shows Time; Steps; Distance; Calories burned; Floors climbed; Very active minutes; Caller ID; and Alarm.

Fitbit Force display modes

The Charge HR's OLED display is much like the Charge but includes extra features. It shows Heart Rate; Exercise Tracking; Time; Steps; Distance; Calories burned; Floors climbed; Very active minutes; Caller ID; and Alarm.

Fitbit Charge HR display screens tracks

The Blaze's colourful display wins hands down, although you won't see it if you put your hands down…

Fitbit Blaze display

The Surge's larger display (below) shows even more data to fitness and sports nuts. Its display is a touch screen monochrome LCD with backlight (for low light visibility).

Fitbit Surge screens

Which Fitbit is best: measurements and specs

While the Fitbit One and Zip are small and can clip onto clothing or sit in your pocket they’re in some ways less flexible than the wristbands. You’re also less prone to forget a fitness wristband than you are a tiny clip-on gadget which inevitably gets left behind when you change your clothes, and we've put several through the washing machine (amazingly, they mostly survived).

The Flex and Alta are thinner and slightly lighter than the Charge. The Flex is 13.99mm wide and the Alta 15mm, compared to the Charge's 21.1mm girth. As the Charge/HR/Surge also include a watch function they might actually save you wrist space as you can ditch your watch.

The Zip is the smallest of the Fitbits – it’s shorter than the One but podgier.

When you buy a Flex you get both a large (161-209mm) and small (140-176mm) wristband, but with the Charge, Charge HR and Surge you need to specify whether you want Small, Large or X-Large, as the tracker itself is built into the band. You choose a S, L or XL tracker for the Alta and Blaze, and can also choose an extra, different strap separately. You can check with Fitbit’s online wristband sizing tool.

Fitbit Zip size and weight: H: 48mm; W: 19.3mm; D: 9.65mm; Weight: 8g.

Fitbit Zip measurements specs size

Fitbit One size and weight: H: 35.5mm; W: 28mm; D: 9.65mm; Weight: 8g.

Fitbit One measurements specs size

Fitbit Flex size and weight: W: 13.99mm; Weight: 29g.

Fitbit Flex measurements specs size

Fitbit Alta size and weight: W: 15mm. Weight dependent on strap choice.

Fitbit Alta bands

Fitbit Alta sizes

Fitbit Charge size and weight: W: 21.1mm; Weight: 24g.

Fitbit Charge wristband tracker

Fitbit Charge size guide wristband

Fitbit Charge HR size and weight: W: 21.1mm; Weight: 26g.

Fitbit Charge HR wristband tracker

Fitbit Charge HR sizes

Fitbit Blaze size and weight: W: 42.1mm. Weight dependent on strap choice, but 43g with Classic Strap.

Fitbit Blaze size guide

Fitbit Surge size and weight: W: 34mm; Weight: 52g.

Fitbit Surge activity tracker wristband

Fitbit Surge sizes

Which Fitbit is best: battery life

Remembering to keep your Fitbit charged is important if you wish to keep your activity tracked. The longer the battery life in between charges the better, then.

The Zip is easily the best for battery life but you will need to buy a new battery two or three times a year. The 3V coin (CR 2025) battery is cheap, though – you can buy a pack of five for under £2.50 (US$3). The other Fitbits feature rechargeable batteries.

Remember that accessing the display on any of the Fitbits will drain the battery faster.

Fitbit One battery life: 5-7 days

Fitbit Zip battery life: 4-6 months

Fitbit Flex battery life: 5 days

Fitbit Charge battery life: 7-10 days

Fitbit Alta battery life: up to 5 days

Fitbit Charge HR battery life: 5+ days

Fitbit Blaze battery life: up to 5 days

Fitbit Surge battery life: Up to 5 days

Which Fitbit is best: water resistance

Sadly none of the Fitbit activity trackers can monitor your swimming. But you can at least wear your Flex in the shower, unlike the other Fitbits that are less happy getting wet. See: Is the Fitbit waterproof?

I did wear my Flex while swimming and after a few months the rubber wristband did begin to perish a little, and my wife claims that it started to smell – so best taken off for long periods of liquid submersion.

The Fitbit One, Zip and Force are splash proof, but should not be submerged more than one metre.

The Flex, Charge, Charge HR and Blaze are water resistant to 1 ATM (Atmosphere), so theoretically can be submerged up to 10 metres (33ft). However, watch specialists advice that a device with this resistance level is protected against accidental exposure to water; for example, splashes, perspiration or accidental immersion; and state that it should not be exposed to any water pressure. I did once jump in a swimming pool with my Charge HR and it survived, but it's not recommended!

The Fitbit Surge is water resistant to 5 ATM, which means it is wearable around household sinks, while playing sports and while swimming in shallow water. Experts recommend that you don't wear it while bathing, snorkeling or scuba diving. 

Which Fitbit is best: colours

The Fitbit One is available in either Burgundy or Black.

Fitbit One model colours

The Fitbit Zip is more colourful, available in either Blue, Magenta, White, Charcoal or Lime.

Fitbit Zip model colours

The Flex wristband is available in ten colours: Black, Slate, Tangerine, Teal, Navy, Violet, Blue, Lime, Pink and Red. You can buy extra bands (without the tracker) for £12.99.

Fitbit Flex colours

The Fitbit Charge is available in Black, Slate, Blue and Burgundy.

Fitbit Charge colours

The Fitbit Alta is available in a classic strap (extra £19.99 or US$29.95) in Black, Blue, Plum or Teal; in leather (extra £49.99/£99.95) in Graphite or Blush Pink); or in Stainless Steel Links (extra £79.99/$129.95).

Fitbit Alta colours

The Fitbit Charge HR is available in Black, Plum, Blue, Tangerine, Teal and Pink.

Fitbit Charge HR new colours

The Fitbit Blaze is available in a classic strap (extra £19.99 or US$29.95) in Black, Blue or Plum; in leather (extra £59.99/£99.95) in Black, Camel or Mist Grey); or in Stainless Steel Links (extra £89.99/$129.95).

Fitbit BLaze Classic straps

Fitbit BLaze Leather straps

Fitbit BLaze Stainless Steel Links strap

The Fitbit Surge is available in three colours: Black, Blue and Tangerine.

Fitbit Surge colours

Which Fitbit is best: what you get in the box

The Fitbit Zip ships with tracker, silicone and metal clip, wireless sync dongle, replaceable battery and battery door tool.

Fitbit Zip box contents

The Fitbit One comes with tracker, silicone and metal clip, wireless sync dongle, charging cord and sleep wristband.

Fitbit One box contents

The Fitbit Flex includes tracker within wristband (small and large), wireless sync dongle, and charging cable.

Fitbit Flex box contents

The Fitbit Charge and Charge HR come with tracker within wristband (either small, large or x-large), wireless sync dongle, and charging cable. For some unknown reason the Charge and Charge HR have different charging cables.

Fitbit Charge accessories

The Fitbit Blaze and Alta ship with a charging cable. You need to specify the type of band (Classic, Leather or Stainless Steel) you require. The Alta also comes with a wireless dongle, although strangely the Blaze does not – it conects via Bluetooth alone.

Fitbit Blaze charging cable box

The Fitbit Surge ships with a wireless sync dongle and charging cable.

Fitbit apps

All the trackers work with the excellent Fitbit desktop dashboard and iPhone, Android and Windows Phone apps.

The apps look wonderful, and display all your daily and historical stats in beautiful graphs that expand in landscape orientation as well as display in portrait view.

The desktop dashboard is another visually atrractive and informative place to monitor your factivity and fitness statistics.

And as added incentive you can link with friends, family and colleagues to compete against each other on the leaderboard, get involved in daily or weekly Challenges, and win badges determined by passing goals, and historical milestones. These aspects of the Fitbit system really set it apart from the other trackers.

Fitbit activity stats and sofware

Losing a Fitbit wristband

Some Fitbits are easier to lose than others. Obviously if you are the sort of person who puts things down and then forgets where they put them, then you'll expect to lose your possessions every now and again. But with Fitbits some are risker than others.

The Zip and One clip to your clothing or can be carried in a pocket, and so could be easier to mislay than something attached to your wrist. The wristbands are certainly less easy to lose, but we recommend you go for one with the watch-like buckle (Charge HR, Blaze, Surge) as these are much more secure than the pop-in clasp (Flex, Alta, Charge).

Fitbit clasp buckle secure lose

Which Fitbit is best for you?

Fitbit Flex - £79.99 / US$99.95 - click here to view on Amazon.
Fitbit Charge - £99.99 / US$129.95 - view on Amazon.
Fitbit Alta - £99.99 / US$129.95 - view on Amazon.
Fitbit Charge HR - £119 / US$149.95 - view on Amazon.
Fitbit Blaze - £159 / US$199.95 - view on Amazon.
Fitbit Surge - £199 / US$249.95. - view on Amazon.
Fitbit One - £79.99 / US$99.95 - view on Amazon.
Fitbit Zip - £49.99 / US$59.95 - view on Amazon.

It’s possible to look at the Fitbit activity trackers in two groups.

The clip-on One and Charge, Charge HR and Surge wristbands boast the most features, including Floors Climbed via the altimeter. They also show more right there on their displays. The Charge, Charge HR, Blaze and Surge also show Call Notifications from your phone, including Caller ID.

The Zip and Flex are cheaper but don’t include the altimeter so climbing lots of stairs will count only as Steps and not as the harder climb. Of course floors climbed counts as Steps on the other trackers, too.

The Zip doesn’t vibrate when you reach your targets. And it doesn’t monitor your sleep efficiency.

The Zip is the cheapest Fitbit, and if you can live without the altimeter and sleep tracking then this is a great entry point. Sleep tracking is fun but not at the top of most people's fitness lists, but the buzz is a great way to know you’ve reached your key target. Is that worth an extra £30 for the One or Flex? That’s really up to you.

Fitbit Flex vs Fitbit Alta vs Charge vs Charge HR vs Blaze vs Surge: When it comes to choosing between the five Fitbit wristbands we love the Flex’s minimalism but think the Charge's better display and altimeter make it worth the extra £20, depending on where you buy it. The new Fitbit Alta combines the slender design of the Flex with a more detailed display, but is quite a step up in price from the Flex.

The Flex is a great activity tracker in its own right, and syncs well with your smartphone and computer. It's also available in more colours.

If you're a keen gym goer or jogger the heart-rate-monitoring Charge HR is just £20 more than the Fitbit Charge. You also get the better strap (buckle) with the HR, and even if you're not a fitness nut the heart-rate monitor is a fun addition, so there's another £20 that could be worth investing. From someone who has lost a wristband I'd go with the most secure strap, and that means either the Charge HR, Blaze or Surge.

The GPS-packing Surge has so much more than the other Fitbits and costs quite a bit more, so is maybe an unfair comparison. It's for real gym fanatics and at least the semi-serious runner. Or you can wear one, and pretend to be a performance fitness nut, and just use it to count your steps and tell you the time.

The Fitbit Blaze is similar to the other Fitbits but comes with a flashier colour display. Its lack of built-in GPS might disappoint some, but most runners take their smartphone with them for music or call, so its wireless connection to the phone's GPS does the same trick. It will apeal to those people who want an activity tracker but also a watch-like timepiece. Its colourful displays are also going to attract attention.

There's a Fitbit tracker for everyone. If you're unsure you can always later sell up and upgrade to a higher-spec Fitbit tracker. Getting fitter now is the main thing, so get started soon.