Fitbit Comparison – Which is the Best Fitbit for Me?


Fitbit are a huge player when it comes to wearable technology. But with so many releases, and features spanning lifestyle, fitness and sleep monitoring, it can be difficult to know which Fitbit product is most suited for your goals. Fear not, my mega product comparison will point you in the right direction.

The Basics – Step Tracking, Calories and Distance

Available on: Zip, One, Flex, Flex 2, Charge, Charge HR, Charge 2, Blaze, Surge, Ionic

These three features are at the foundation of all Fitbit devices, so you’ll find them across all releases. Though often tracked from the wrist, the Zip measures from the waist, and the One from belt, pocket or bra.

While steps captured are based on movement, the distance and calorie metrics are algorithm dependent and can be affected by information you input into the Fitbit app such as height, weight gender and age. Though all releases provide these metrics, expect to see improved distance accuracy in later releases with GPS connectivity and improved calorie estimates in later releases with PurePulse heart rate technology.

SmartTrack – Automatic exercise detection

Available on Flex 2, Alta, Alta HR, Charge 2, Blaze, Surge, Ionic

As activity trackers have evolved, they’ve become better at recognising movements automatically. SmartTrack is a valuable timesaver meaning activities big and small are synched to Fitbit profile without having to record them. SmartTrack currently filters exercise movements into six categories.

  • Walking
  • Running
  • Elliptical
  • Swimming
  • Sport
  • Aerobic workout

Whilst the first four movements are repetitive motions, sport and aerobic workouts capture periods which are less identifiable such as kickboxing, tennis or football. Post workout, you have the option to label these up properly within the app.

SmartTrack is great for crediting you during those moments you wouldn’t normally count as exercise. A walk during your lunch break can still do wonders for your health, so why not count it? When you’re planning to do an intensive workout, I’d still recommended that you record the workout manually, just because you’ll get more insightful data; for instance heart rate tracking goes from every 5 seconds to every second when in activity mode.

Which Fitbit measure swimming activity?

With 50m water resistance, the Flex 2 and Ionic are the only Fitbit devices designed to track swimming activity. The SmartTrack algorithm will detect when you’ve done at least 10 minutes swimming and upload the activity to your Fitbit profile. Both the Flex 2 and Ionic can measure swim duration and lengths in the pool; from these metrics they can calculate out your swim distance and pace.

Fitbit Ionic - Best for swimming

Fitbit Ionic having a splash in the pool

Do Fitbit products have GPS?

GPS is great for accurately measuring distance based activities such as running or cycling. The Fitbit product range offers two very different methods for tracking distance via GPS.

Connected GPS

This is the most common method, where the Fitbit wearable “piggybacks” the signal from your mobile phone. Accurate for tracking those miles or kilometres but does mean you have to keep your mobile phone in close proximity for the whole workout. Not a problem if you’re cycling but runners may feel uncomfortable on faster paced workouts.

Available in: Fitbit Blaze, Charge 2

GPS in watch – Fitbit Ionic and Fitbit Surge

If your exercise routine involves regular running mileage, you’ll likely prefer having a built in GPS chip in your Fitbit. Get the distance and pace stats without needing to carry your phone. Post-workout, just connect your wearable to your phone and it’ll upload all your running stats straight to your Fitbit profile.

Available on: Fitbit Ionic, Surge

Which Fitbit products track Floors Climbed?

If you want the motivation to take the stairs instead of the elevator, this feature uses an altimeter sensor to detect changes in elevation. It only counts going up stairs (not down) as its the climbing which requires more effort. Sadly it won’t track those StairMaster machines in the gym either as there are no significant changes in elevation.

Available in Charge 2, Blaze, Surge, Ionic

Do Fitbits measure heart rate?

Using PurePulse technology, some Fitbits measure a pulse reading directly from the wrist. Heart rate data adds a useful layer of context into your routine, helping you to understand how intense your body is working. It also enables you to credit exercise to non-step based activities such as circuit training or rowing, thanks to an increase in heart rate.

Available in: Alta HR, Charge HR, Charge 2, Blaze, Surge, Ionic

Cardio Fitness Level

Available on: Charge 2, Blaze, Alta HR and Fitbit Ionic

Using the Fitbit app, its possible to get a reading of your Cardio Fitness Score, an equivalent of VO2 Max, which is how efficient your body uses oxygen during intense exercise. A VO2 max score is a useful metric for endurance athletes, and is often conducted in a sports science lab with a treadmill, Douglas bags and heart rate monitor. Though I’m sceptical Fitbit can replicate the test with the same level of precision, their approach is accessible to more people, can be tested anywhere. and more frequently.

Fitbit collects a basic Cardio Fitness Score using:

  • Resting heart rate (Captured during sleep)
  • Age
  • Gender
  • Weight

For a more precise measurement of VO2 max score, Blaze, Charge 2 and Ionic wearers can use the GPS functionality in their phone to go for a running test. A run of at least 10 minutes on a flat surface will give the most reliable results.

The Fitbit app stores your results over time, so its easy to monitor improvements in your cardiovascular health. You can also compare your score against anonymous users of the same gender and age for added context on your result.

Relax - Yoga - Fitbit Charge 2

Guided Breathing Sessions

Available on Charge 2 and Fitbit Ionic

We focus so much time exercising many muscles, but often neglect any focus on those which help us to breathe. The Charge 2 has a setting with two mini-workouts which focus purely on inhaling and exhaling deeply to lower heart rate. More about that in my comparison of Charge HR and Charge 2.


Multi-Sport is all about being able to view a workout in real time. If you’re running or cycling, you could see how long you’ve been exercising for. If the Fitbit has heart rate stats, you might be able to see your pulse reading. Useful to know if you need feedback on your workout in the moment.

Available on Charge, Charge 2, Blaze, Surge, Ionic

Reminders to Move

I think we’re all guilty sometimes of spending too long on the sofa (Netflix binge anyone?). Fitbit encourage users do at least 250 steps per hour during a 9 hour period of your choice. If you’ve been a bit too relaxed, the wearable will notify you to get up and walk around for a few minutes. Think of it as a gentle nudge.

Available on: Flex 2, Alta, Alta HR, Charge 2, Blaze, Ionic

Sleep Tracking on Fitbit

Basic sleep tracking

Available on: One, Flex 2, Alta, Alta HR, Charge 2, Blaze, Surge, Ionic

Most Fitbit releases, even the older ones, have an element of sleep tracking. Its a core feature, that calculates the number of hours you spend asleep based on how much you move.

The Silent Alarm feature wakes you with a little vibration. Beats a noisy alarm clock, and is pretty useful if you’re getting up ridiculously early for a morning workout.

More advanced sleep tracking features

Available on: Alta HR, Charge 2, Blaze, Ionic

Some Fitbit releases go more granular to distinguish sleep stages. More detailed tracking on your sleeping movements allows these wearables to calculate time spent within Light, Deep and REM phases of sleep.

Fitstar – On Screen Workouts

Available on Blaze and Ionic

Select the Fitstar app when wearing the Blaze, and you’ll be able to use 3 basic workouts which are pre-installed.

  • Warm Up
  • 7 minute workout
  • 10 minute Abs

Routines can be paused should you need to catch your breath, and exercises can even be skipped if needed. Post workout, you can review your stats such as average/maximum heart rate, calories burned and length of workout.

Further routines can be downloaded from the Fitstar website for a monthly subscription, like the yoga or personal trainer series.

Which Fitbit models tell the time?

Available on: Zip, Alta, Alta HR, Charge HR, Charge 2, Blaze, Surge
Do you need to wear a watch and a fitness wearable if a Fitbit can do both? The majority of Fitbit releases have a clock display that’s easily accessible. On the smaller screened Alta, Charge and Zip series these are a simple digitised number format HH:MM. The Blaze and Surge with their bigger screens allow great customisation; such as clock faces and different wallpapers.

Which Fitbit wearables can’t tell the time?

A clock shouldn’t be a feature assumed on Fitbit wearables. The Flex 2 and original Flex both arrive without this functionality, likely due to their more basic display which comprises of a few LED lights.

Which Fitbit devices have call and text notifications?

Flex 2, Alta, Alta HR, Charge 2, Blaze Surge, Ionic

Which Fitbit devices play music?

Available on: Ionic, Blaze, Surge.
Listening to music whilst exercising may help to motivate you during those tough sessions, cue lonely long mileage runs or a circuit routine that makes you want to vomit!

Fitbit Flyer Headphones - Play Music on Fitbit

The Ionic is the only Fitbit release currently which lets you upload your power playlist onto the watch for easy playback. With a claimed capacity of 300+ songs, there’s enough variety to keep you fired up. It’s super useful if you’re planning to do a long workout without being in range of your phone. For other releases with the same feature check out my guide to the top sports watches that can play music

The Blaze and Surge wearables can’t store music on the watch. Instead you Bluetooth connect the Fitbit to your phone and use the wearable to remote control your playlists. Play, pause and skip tracks using a Fitbit; its more convenient for workouts than reaching for your phone.


About Author

I'm a super keen injured runner with over 20 years experience in races and endurance training. Get in touch with me over Twitter, G+ on in the comments below.

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