Scored using Fitness trackers Methodology v1.0
Fitness trackers Methodology v1.0
Mathematical & Unbiased Scoring
Products in this category are evaluated mathematically under Frontumo Fitness trackers Methodology v1.0 using verified laboratory benchmarks, technical specifications, and authentic consumer ratings with 0% commercial bias.
Explore Fitness trackers Methodology v1.0

Fitbit Flex Review | 171 Data compared

Avg. price:~£80Battery life:5 daysScreen size:?Heart rate monitor:noGPS:noWaterproof depth rating:10 m

Fitbit Flex Review: Compare 171 technical specifications and user reviews to see how this product ranks in the Fitness trackers category and whether it is worth buying.

6.5

Overall score

Score
6.5/ 10
✕
What it is
An overall evaluation of the fitness tracker's quality, based on technical analyses and user reviews.
When it matters
When you need a quick reference to identify the best fitness trackers on the market.
Score distribution
â–¼
<55-66-77-88-99-10
Score components

80%

6.0

Technical score

20%

8.5

User score

â–¼Worse than 72% of fitness-trackers
6.0

Technical score

Technical score
6.0/ 10
✕
What it is
An assessment of technical performance for products in the Fitness trackers category across these key areas: Health, Sports & Navigation, Smart Features, App & Wellness, Connectivity, Battery, Display, Design & Durability.
When it matters
When you want to compare fitness trackers based on technical performance and available features.
Score distribution
â–¼
<55-66-77-88-99-10
Score components

20%

7.5

Sports & Navigation

20%

4.2

Battery

18%

5.2

Health

18%

5.1

Display

8%

5.0

Smart Features

8%

8.2

App & Wellness

4%

9.1

Connectivity

4%

8.2

Design & Durability

â–¼Worse than 89% of fitness-trackers
8.5

User score

User score
8.5/ 10
✕
What it is
A rating that combines user reviews and the total number of reviews received by the fitness tracker.
When it matters
When you want to know how a fitness tracker performs in daily use and how reliable it remains over time according to user feedback.
Score distribution
â–¼
<55-66-77-88-99-10
Score components

70%

8.2

User ratings

30%

9.3

Number of reviews

Based on 6,242 buyer reviews from online shops.
How we calculate this
User ratings – average star rating across all shop listings, weighted by how many reviews each has, on a 1–10 scale.
Number of reviews – how many buyer reviews the product has, on a logarithmic scale; the 8% most-reviewed models in the category get 10.
â–²Better than 80% of fitness-trackers
  • fitbit-flex
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Technical Specifications of fitness tracker Fitbit Flex

Technical score
Technical score
6.0/ 10
✕
What it is
An assessment of technical performance for products in the Fitness trackers category across these key areas: Health, Sports & Navigation, Smart Features, App & Wellness, Connectivity, Battery, Display, Design & Durability.
When it matters
When you want to compare fitness trackers based on technical performance and available features.
Score distribution
â–¼
<55-66-77-88-99-10
Score components:

20%

7.5

Sports & Navigation

20%

4.2

Battery

18%

5.2

Health

18%

5.1

Display

8%

5.0

Smart Features

8%

8.2

App & Wellness

4%

9.1

Connectivity

4%

8.2

Design & Durability

6.0
User score
User score
8.5/ 10
✕
What it is
A rating that combines user reviews and the total number of reviews received by the fitness tracker.
When it matters
When you want to know how a fitness tracker performs in daily use and how reliable it remains over time according to user feedback.
Score distribution
â–¼
<55-66-77-88-99-10
Score components

70%

8.2

User ratings

30%

9.3

Number of reviews

Based on 6,242 buyer reviews from online shops.
How we calculate this
User ratings – average star rating across all shop listings, weighted by how many reviews each has, on a 1–10 scale.
Number of reviews – how many buyer reviews the product has, on a logarithmic scale; the 8% most-reviewed models in the category get 10.
8.5
Popularity
Popularity
9.3/ 10
✕
What it is
An indicator based on the number of reviews received by the fitness tracker.
When it matters
When you prefer to buy a product chosen and reviewed by many other consumers.
Score distribution
â–¼
<55-66-77-88-99-10
Popularity:
Fitbit Flex has a popularity score of 9.3 points, which is higher than 82.6% of fitness trackers.
9.3
Value for money
Value for money
7.5/ 10
✕
What it is
An indicator that combines the fitness tracker's overall rating with its cost.
When it matters
When you are looking for a fitness tracker with a good balance between quality and price.
Score distribution
â–¼
<55-66-77-88-99-10
Score components:

60%

6.5

Overall score

40%

10

Price

7.5
Heart rate monitor
no
Heart rate monitor
no
This fitness tracker does not support heart rate monitoring. 60.3% of fitness trackers support heart rate monitoring.
Resting heart rate
no
Resting heart rate
no
This fitness tracker does not support Resting heart rate. 47.9% of fitness trackers support Resting heart rate.
Fast/slow heart rate alerts
no
Fast/slow heart rate alerts
no
This fitness tracker does not support high and low heart rate alerts. 34.7% of fitness trackers support high and low heart rate alerts.
Irregular heart rate alerts
no
Irregular heart rate alerts
no
This fitness tracker does not support irregular heart rate alerts. 12.4% of fitness trackers support irregular heart rate alerts.
Blood oxygen sensor
no
Blood oxygen sensor
no
This fitness tracker does not have a blood oxygen sensor. 25.4% of fitness trackers have a blood oxygen sensor.
Show more
GPS
no
GPS
no
This fitness tracker does not have GPS. 11% of fitness trackers have GPS.
Satellite systems supported
no
Satellite systems supported
no
This fitness tracker supports no satellite systems which is less versatile than that of 12.2% of fitness trackers and the same as that of 87.8% of fitness trackers.
GNSS bands supported
?
Galileo support
no
Galileo support
no
This fitness tracker does not support Galileo. 4.9% of fitness trackers support Galileo.
Acquires GPS faster
no
Acquires GPS faster
no
This fitness tracker does not support faster GPS acquisition. 8.1% of fitness trackers support faster GPS acquisition.
Show more
Notifications
no
Notifications
no
This fitness tracker does not support notifications. 73% of fitness trackers support notifications.
Vibrating alerts
yes
Vibrating alerts
yes
This fitness tracker supports vibration alerts. 16.3% of fitness trackers support vibration alerts.
Call control
no
Call control
no
This fitness tracker does not support call controls. 41.8% of fitness trackers support call controls.
Call answering
no
Call answering
no
This fitness tracker does not support call answering. 1% of fitness trackers support call answering.
Calendar sync
no
Calendar sync
no
This fitness tracker does not support calendar sync. 20.3% of fitness trackers support calendar sync.
Show more
Activity reports
yes
Activity reports
yes
This fitness tracker supports activity reports. 5.7% of fitness trackers support activity reports.
via Fitbit app
Goal setting
yes
Goal setting
yes
This fitness tracker supports goal setting. 2.4% of fitness trackers support goal setting.
Achievements
yes
Achievements
yes
This fitness tracker supports achievements. 24.3% of fitness trackers support achievements.
Inactivity alerts
no
Inactivity alerts
no
This fitness tracker does not support inactivity alerts. 77% of fitness trackers support inactivity alerts.
Coaching
no
Coaching
no
This fitness tracker does not support coaching. 34% of fitness trackers support coaching.
Show more
Bluetooth version
4
Bluetooth version
4
This fitness tracker supports Bluetooth 4 which is newer than in 5.1% of fitness trackers and equal to that in 51.3% of fitness trackers.
Maximum Bluetooth range
20 m
Maximum Bluetooth range
20 m
This fitness tracker offers a Bluetooth range of 20 m which is higher than that of 80.6% of fitness trackers and equal to that of 6.7% of fitness trackers.
NFC
yes
NFC
yes
This fitness tracker has NFC. 87.5% of fitness trackers have NFC.
NFC is for pairing only.
Wi-Fi connectivity
no
Wi-Fi connectivity
no
This fitness tracker does not support Wi-Fi. 1.8% of fitness trackers support Wi-Fi.
Wi-Fi version
?
Show more
Battery life
5 days
Battery life
5 days
This fitness tracker offers a battery life of 5 days which is shorter than that of 79.2% of fitness trackers and equal to that of 12.4% of fitness trackers.
Battery life with GPS on
N/A
Battery life in training mode
?
Battery life in power-saving mode
N/A
Battery capacity
?
Show more
Display
no
Display
no
This fitness tracker does not have a display. 76.4% of fitness trackers have a display.
Screen size
?
Display type
N/A
Screen resolution
N/A
Pixel density
N/A
Show more
Form factor
wristband
Hybrid design
no
Hybrid design
no
This fitness tracker does not support Hybrid design. 2.4% of fitness trackers support Hybrid design.
Designed for kids
no
Designed for kids
no
This fitness tracker is not designed for kids. 2.4% of fitness trackers are designed for kids.
Replaceable watch band
yes
Replaceable watch band
yes
This fitness tracker has a replaceable watch band. 25.6% of fitness trackers have a replaceable watch band.
Band width
11 mm
Show more

Fitbit Flex vs the average fitness tracker

246810TotalHealthSports & NavigationBatteryDisplayConnectivitySmart FeaturesDesign & DurabilityApp & Wellness
  • 44% lighter
    Thickness
    14 g mm
    This fitness tracker is lighter than the average fitness tracker (14 g vs 25 g). The average fitness tracker weighs 25 g.
    14 g vs 25 g
  • Tracks menstrual cycle
    Menstrual cycle tracking
    yes
    This fitness tracker supports menstrual cycle tracking, while the average fitness tracker does not. 41.7% of fitness trackers support menstrual cycle tracking.
  • Windows compatible
    Compatible with Windows
    yes
    This fitness tracker is compatible with Windows, while the average fitness tracker is not. 22.3% of fitness trackers are compatible with Windows.
    Via Fitbit Connect.
  • Mac OS X compatible
    Compatible with Mac OS X
    yes
    This fitness tracker is compatible with Mac OS X, while the average fitness tracker is not. 28.8% of fitness trackers are compatible with Mac OS X.
    Via Fitbit Connect.
  • NFC
    NFC
    yes
    This fitness tracker has NFC, while the average fitness tracker does not. 13% of fitness trackers have NFC.
    NFC is for pairing only.
  • 10 m longer Bluetooth range
    Maximum Bluetooth range
    20 m
    This fitness tracker has a longer Bluetooth range than the average fitness tracker (20 m vs 10 m). The average fitness tracker offers a Bluetooth range of 10 m.
    20 m vs 10 m
  • Cycle start prediction
    Predicts start date
    yes
    This fitness tracker predicts the start date, while the average fitness tracker does not. 42.5% of fitness trackers predict the start date.
  • Ovulation prediction
    Predicts ovulation
    yes
    This fitness tracker predicts ovulation, while the average fitness tracker does not. 41.6% of fitness trackers predict ovulation.
  • 6.6% higher user score
    User score
    8.5/ 10
    ✕
    What it is
    A rating that combines user reviews and the total number of reviews received by the fitness tracker.
    When it matters
    When you want to know how a fitness tracker performs in daily use and how reliable it remains over time according to user feedback.
    Score distribution
    â–¼
    â–¼
    <55-66-77-88-99-10
    Fitbit Flex
    the average fitness tracker
    Fitbit Flex has a higher user score than the average fitness tracker (8.52 vs 8.000).
    8.52 vs 8
  • 83.3% more popular
    Fitbit Flex has a higher popularity than the average fitness tracker (9.28 vs 5.1).
    9.28 vs 5.07
  • Tracks menstrual cycle
    Menstrual cycle tracking
    yes
    This fitness tracker supports menstrual cycle tracking, while the average fitness tracker does not. 41.7% of fitness trackers support menstrual cycle tracking.
  • Ovulation prediction
    Predicts ovulation
    yes
    This fitness tracker predicts ovulation, while the average fitness tracker does not. 41.6% of fitness trackers predict ovulation.
  • Cycle start prediction
    Predicts start date
    yes
    This fitness tracker predicts the start date, while the average fitness tracker does not. 42.5% of fitness trackers predict the start date.
  • Windows compatible
    Compatible with Windows
    yes
    This fitness tracker is compatible with Windows, while the average fitness tracker is not. 22.3% of fitness trackers are compatible with Windows.
    Via Fitbit Connect.
  • Mac OS X compatible
    Compatible with Mac OS X
    yes
    This fitness tracker is compatible with Mac OS X, while the average fitness tracker is not. 28.8% of fitness trackers are compatible with Mac OS X.
    Via Fitbit Connect.
  • NFC
    NFC
    yes
    This fitness tracker has NFC, while the average fitness tracker does not. 13% of fitness trackers have NFC.
    NFC is for pairing only.
  • 10 m longer Bluetooth range
    Maximum Bluetooth range
    20 m
    This fitness tracker has a longer Bluetooth range than the average fitness tracker (20 m vs 10 m). The average fitness tracker offers a Bluetooth range of 10 m.
    20 m vs 10 m
  • Firmware update method
    Firmware update method
    over-the-air / USB
    This fitness tracker uses a more convenient firmware update method than the average fitness tracker (over-the-air / USB vs over-the-air). The average fitness tracker uses over-the-air for firmware updates.
    over-the-air / USB vs over-the-air
  • 44% lighter
    Thickness
    14 g mm
    This fitness tracker is lighter than the average fitness tracker (14 g vs 25 g). The average fitness tracker weighs 25 g.
    14 g vs 25 g
  • 29.8 mm lower height
    Height
    11 mm
    This fitness tracker is shorter than the average fitness tracker (11 mm vs 40.8 mm). The average fitness tracker has a height of 40.8 mm.
    11 mm vs 40.8 mm
  • Tracks calorie intake
    Calorie intake tracking
    yes
    This fitness tracker supports calorie intake tracking, while the average fitness tracker does not. 39.3% of fitness trackers support calorie intake tracking.
  • Ad-free
    Free app
    yes
    This fitness tracker has an ad-free app, while the average fitness tracker does not. 48.1% of fitness trackers have an ad-free app.
  • No heart rate monitoring
    Heart rate monitor
    no
    This fitness tracker does not support heart rate monitoring, while the average fitness tracker does. 60% of fitness trackers support heart rate monitoring.
  • No automatic activity detection
    Automatic activity detection
    no
    This fitness tracker does not support automatic activity detection, while the average fitness tracker does. 52% of fitness trackers support automatic activity detection.
  • 5 days shorter battery life
    Battery life
    5 days
    This fitness tracker has a lower battery life than the average fitness tracker (5 days vs 10 days). The average fitness tracker has 10 days of battery life.
    5 days vs 10 days
  • No notifications
    Notifications
    no
    This fitness tracker does not support notifications, while the average fitness tracker does. 72.6% of fitness trackers support notifications.
  • No sleep reports
    Provides sleep reports
    no
    This fitness tracker does not support sleep reports, while the average fitness tracker does. 84.8% of fitness trackers support sleep reports.
  • No battery level indicator
    Battery level indicator
    no
    This fitness tracker does not have a battery level indicator, while the average fitness tracker does. 87.2% of fitness trackers have a battery level indicator.
  • No personalization options
    Can be personalised
    no
    This fitness tracker cannot be personalized, while the average fitness tracker can. 79.9% of fitness trackers can be personalized.
  • 40 m lower waterproof depth rating
    Waterproof depth rating
    10 m
    This fitness tracker has a lower waterproof depth rating than the average fitness tracker (10 m vs 50 m). The average fitness tracker has a waterproof depth rating of 50 m.
    10 m vs 50 m
  • 5.2% worse value for money
    Fitbit Flex has a lower value-for-money score than the average fitness tracker (7.53 vs 7.9).
    7.53 vs 7.92
  • No heart rate monitoring
    Heart rate monitor
    no
    This fitness tracker does not support heart rate monitoring, while the average fitness tracker does. 60% of fitness trackers support heart rate monitoring.
  • No sleep reports
    Provides sleep reports
    no
    This fitness tracker does not support sleep reports, while the average fitness tracker does. 84.8% of fitness trackers support sleep reports.
  • 5 days shorter battery life
    Battery life
    5 days
    This fitness tracker has a lower battery life than the average fitness tracker (5 days vs 10 days). The average fitness tracker has 10 days of battery life.
    5 days vs 10 days
  • No battery level indicator
    Battery level indicator
    no
    This fitness tracker does not have a battery level indicator, while the average fitness tracker does. 87.2% of fitness trackers have a battery level indicator.
  • No display
    Display
    no
    This fitness tracker does not have a display, while the average fitness tracker does. 76.1% of fitness trackers have a display.
  • No notifications
    Notifications
    no
    This fitness tracker does not support notifications, while the average fitness tracker does. 72.6% of fitness trackers support notifications.
  • No stopwatch
    Stopwatch
    no
    This fitness tracker does not have a stopwatch, while the average fitness tracker does. 59.7% of fitness trackers have a stopwatch.
  • 40 m lower waterproof depth rating
    Waterproof depth rating
    10 m
    This fitness tracker has a lower waterproof depth rating than the average fitness tracker (10 m vs 50 m). The average fitness tracker has a waterproof depth rating of 50 m.
    10 m vs 50 m
  • 20 °C higher minimum operating temperature
    Min operating temperature
    -20 °C
    This fitness tracker has a higher minimum operating temperature than the average fitness tracker (-20 °C vs 0 °C). The average fitness tracker supports a minimum operating temperature of 0 °C.
    -20 °C vs 0 °C
  • 3 older release date
    Release date
    2013
    This fitness tracker was released earlier than the average fitness tracker (2013 vs 2016). The average fitness tracker was released in 2016.
    May 2013
    2013 vs 2016
  • No personalization options
    Can be personalised
    no
    This fitness tracker cannot be personalized, while the average fitness tracker can. 79.9% of fitness trackers can be personalized.
  • No inactivity alerts
    Inactivity alerts
    no
    This fitness tracker does not support inactivity alerts, while the average fitness tracker does. 76.6% of fitness trackers support inactivity alerts.

Video reviews

Hands-on testing, unboxing, and real-world video evaluations

Expert reviews

In-depth analysis and verdict from leading tech publications

B
breakingeighty.com
04/05/2021
Summary of the review
I
itstactical.com
07/08/2014
Summary of the review
E
expertreviews.co.uk
18/06/2019
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T
techradar.com
17/11/2017
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T
t3.com
16/10/2015
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T
theguardian.com
14/07/2014
Summary of the review
P
pcmag.com
06/05/2013
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C
cnet.com
06/05/2013
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C
cnet.com
12/05/2013
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W
wired.com
06/05/2013
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L
linustechtips.com
04/10/2013
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irishtimes.com
17/10/2013
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L
livescience.com
02/10/2013
Summary of the review
L
laptopmag.com
05/05/2013
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T
theverge.com
06/05/2013
Summary of the review
M
medium.com
19/12/2014
Summary of the review
C
connect.de
19/05/2014
Summary of the review
H
heise.de
24/10/2013
Summary of the review
D
diegesundheitsexperten.com
18/10/2013
Summary of the review
C
chip.de
20/07/2013
Summary of the review
C
chip.de
22/08/2014
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L
lesnumeriques.com
07/12/2013
Summary of the review
J
journaldugeek.com
03/06/2013
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T
trentejours.com
30/07/2014
Summary of the review
T
trailandrunning.com
10/12/2021
Summary of the review
0
01net.com
29/07/2014
Summary of the review
P
pixel-geek.fr
30/08/2015
Summary of the review
C
colineetsondino.wordpress.com
14/05/2014
Summary of the review
T
treki23.com
20/03/2014
Summary of the review
X
xataka.com.mx
09/05/2014
Summary of the review
F
forbes.com.mx
20/09/2014
Summary of the review
E
es.gizmodo.com
10/05/2013
Summary of the review
X
xataka.com
07/06/2013
Summary of the review
N
nextgentech.it
05/09/2016
Summary of the review
D
dday.it
04/08/2014
Summary of the review
M
macitynet.it
18 March 2026*
Summary of the review
T
tweakers.net
30/06/2014
Summary of the review
P
portablegear.nl
Unknown
Summary of the review
N
natuurlijklinda.nl
23/10/2016
Summary of the review
C
coolesuggesties.nl
06/09/2014
Summary of the review
A
androidworld.nl
02/07/2013
Summary of the review
T
tweakers.net
01/01/2018
Summary of the review

Third-party reviews

Based on 6,242 buyer reviews from online shops.
Reviews last updated: June 2026 · How we calculate this

What we like about Fitbit Flex

  • Lightweight and comfortable for 24/7 wear
  • Water-resistant design allows for use in the shower or rain
  • Intuitive and comprehensive mobile app and web dashboard
  • Effective 'Silent Alarm' feature that wakes users with vibrations
  • Motivational goal-tracking via five LED progress indicator dots
  • Customisable look with a variety of interchangeable coloured bands
  • Good battery life, typically lasting between 5 to 7 days

What we don't like about Fitbit Flex

  • No built-in display to see real-time stats or time of day
  • Lacks an altimeter, meaning it cannot track floors or stairs climbed
  • Uses a proprietary charging cradle that is easy to lose and hard to replace
  • Sleep tracking often requires manual activation through the app or device tapping
  • Step accuracy can be affected by non-walking movements like typing or arm gestures
  • The wristband clasp can be difficult and awkward to fasten securely
  • No integrated heart rate monitor

Verdict

The Fitbit Flex is a minimalist, screenless activity and sleep tracker featuring a 3-axis accelerometer, five-LED indicator lights for goal tracking, and Bluetooth 4.0 for wireless syncing with mobile devices. Its primary characteristics include tracking daily steps, distance, calories burned, and active minutes, alongside a silent vibrating alarm and automatic sleep monitoring. Major pros include a lightweight, comfortable design with interchangeable bands, a solid 5-day battery life, and a robust supporting app ecosystem for data analysis and food logging. However, common cons include the lack of a proper digital display or altimeter for tracking stairs, a proprietary charging cable, and a strap clasp that many users find difficult to secure.

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