OVERALL
ALTERNATIVES
SPECS
VS AVERAGE
REVIEWS
Scored using Smartwatches Methodology v2.0
Smartwatches Methodology v2.0
Mathematical & Unbiased Scoring
Products in this category are scored under Frontumo Smartwatches Methodology v2.0: technical specifications plus grades from 3,488 independent expert reviews and 5,192 video reviews, with 0% commercial bias.
Explore Smartwatches Methodology v2.0

Apple Watch Series 4 40mm Review | 126 Data compared

Avg. price:~£160Screen size:1.57 inchBattery life:0.75 daysDisplay type:OLED

Apple Watch Series 4 40mm Review: Compare 126 technical specifications and 22 expert and video reviews to see how this product ranks in the Smartwatches category and whether it is worth buying.

7.6

Overall score

Score
7.6/ 10
✕
What it is
An overall evaluation of the smartwatch's quality, based on technical analyses and user reviews.
When it matters
When you need a quick reference to identify the best smartwatches on the market.
Score distribution
â–¼
<55-66-77-88-99-10
â–² Better than 77% of models
Score components

70%

7.2

Technical score

30%

8.6

Review score ( 10 · 12)

Review score 30% · 8.6 · based on 22 independent reviews
Every model in this category gets the same split: reviews 30%, technical score 70%. This model has enough reviews, so its review score is the weighted average of their grades. 17 more reviews are not scored yet.
â–²Better than 77% of smartwatches
7.2

Technical score

Technical score
7.2/ 10
✕
What it is
An assessment of the smartwatchx27s technical performance, covering seven key areas: health, fitness, display & design, hardware, battery, smart features and connectivity.
When it matters
When you want to compare smartwatches based on technical performance and available features.
Score distribution
â–¼
<55-66-77-88-99-10
â–² Better than 70% of models
Score components

24%

6.0

Health

21%

9.8

Fitness

16%

3.5

Battery

14%

8.6

Smart features

12%

8.3

Connectivity

9%

7.3

Display & Design

4%

6.5

Hardware

â–²Better than 70% of smartwatches
8.6

Review score

Review score
8.6/ 10
✕
What it is
Average grade from independent test sites, magazines and video reviewers, 1–10.
How we count it
Grades: Each review's own score is converted to 1–10; without one, we grade the review ourselves.
Weighting: Big test sites count more, short reviews half as much as full tests. A video review counts half.
Share: Reviews are 30% of the overall score for every model in this category; each of the 5 needed reviews that is missing counts as 7/10.
Score distribution
â–¼
<55-66-77-88-99-10
★ Better than 95% of models
Grades by review (22)
10 reviews: 7 with a printed score, 3 estimated from the review. 12 video reviews, each counting half as much as a written test. Share in the overall score: 30%, the same for every model in this category.
Text reviews 9
✓ explicit
6

7.9%

9.0

tomsguide.com

7.9%

9.0

techradar.com

7.9%

9.0

trustedreviews.com

7.9%

9.0

techadvisor.com

6.3%

8.0

cyclist.co.uk

6.3%

8.0

irishtimes.com

≈ estimated
3

7.9%

9.0

techgearlab.com

6.3%

9.0

thesweetsetup.com

3.2%

7.0

choose.co.uk

Video reviews 2

3.2%

9.0

Mark's Tech Vlogs

1.6%

8.0

Digital Trends

estimated from the review
Shop star ratings are not part of this score.
★Better than 95% of smartwatches
  • apple-watch-series-4-40mm
  • apple-watch-series-4-40mm
apple-watch-series-4-40mm
apple-watch-series-4-40mm

Best prices

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Best rankings

Available: ranking among products currently available (including other versions of this product).All: ranking among all products in the database.
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Technical Specifications of smartwatch Apple Watch Series 4 40mm

Technical score
Technical score
7.2/ 10
✕
What it is
An assessment of the smartwatchx27s technical performance, covering seven key areas: health, fitness, display & design, hardware, battery, smart features and connectivity.
When it matters
When you want to compare smartwatches based on technical performance and available features.
Score distribution
â–¼
<55-66-77-88-99-10
â–² Better than 70% of models
Score components:

24%

6.0

Health

21%

9.8

Fitness

16%

3.5

Battery

14%

8.6

Smart features

12%

8.3

Connectivity

9%

7.3

Display & Design

4%

6.5

Hardware

7.2
Review score
Review score
8.6/ 10
✕
What it is
Average grade from independent test sites, magazines and video reviewers, 1–10.
How we count it
Grades: Each review's own score is converted to 1–10; without one, we grade the review ourselves.
Weighting: Big test sites count more, short reviews half as much as full tests. A video review counts half.
Share: Reviews are 30% of the overall score for every model in this category; each of the 5 needed reviews that is missing counts as 7/10.
Score distribution
â–¼
<55-66-77-88-99-10
★ Better than 95% of models
Grades by review (22)
10 reviews: 7 with a printed score, 3 estimated from the review. 12 video reviews, each counting half as much as a written test. Share in the overall score: 30%, the same for every model in this category.
Text reviews 9
✓ explicit
6

7.9%

9.0

tomsguide.com

7.9%

9.0

techradar.com

7.9%

9.0

trustedreviews.com

7.9%

9.0

techadvisor.com

6.3%

8.0

cyclist.co.uk

6.3%

8.0

irishtimes.com

≈ estimated
3

7.9%

9.0

techgearlab.com

6.3%

9.0

thesweetsetup.com

3.2%

7.0

choose.co.uk

Video reviews 2

3.2%

9.0

Mark's Tech Vlogs

1.6%

8.0

Digital Trends

estimated from the review
Shop star ratings are not part of this score.
8.6
Popularity
Popularity
5.2/ 10
✕
What it is
An indicator based on the number of reviews received by the smartwatch.
When it matters
When you prefer to purchase a product chosen and reviewed by many other consumers.
Score distribution
â–¼
<55-66-77-88-99-10
â–¼ Worse than 57% of models
Popularity:
Apple Watch Series 4 40mm has a popularity of 5.2 points, which is lower than 56.2% of smartwatches.
5.2
Value for money
Value for money
8.2/ 10
✕
What it is
An indicator that combines the smartwatch's overall rating with its cost.
When it matters
When you are looking for a smartwatch with a good balance between quality and price.
Score distribution
â–¼
<55-66-77-88-99-10
â–² Better than 79% of models
Score components:

60%

7.6

Overall score

40%

9.7

Price

8.2
Brand name
Apple
Heart rate monitor
yes
Heart rate monitor
yes
â–² Better than 11% of models
This smartwatch includes a heart rate monitor. 10.5% of smartwatches include a heart rate monitor.
Blood oxygen monitoring
no
Blood oxygen monitoring
no
â–¼ Worse than 67% of models
This smartwatch does not support blood oxygen monitoring. 66.8% of smartwatches support blood oxygen monitoring.
ECG
yes
ECG
yes
â–² Better than 84% of models
This smartwatch supports ECG. 83.6% of smartwatches support ECG.
Irregular heart rate warnings
yes
Irregular heart rate warnings
yes
â–² Better than 52% of models
This smartwatch supports irregular heart rate warnings. 51.9% of smartwatches support irregular heart rate warnings.
Show more
What reviewers say
Accelerometer
yes
Accelerometer
yes
â–² Better than 1% of models
This smartwatch includes an accelerometer. 0.6% of smartwatches include an accelerometer.
Barometer
yes
Barometer
yes
â–² Better than 51% of models
This smartwatch includes a barometer. 50.6% of smartwatches include a barometer.
Gyroscope
yes
Gyroscope
yes
â–² Better than 30% of models
This smartwatch includes a gyroscope. 30.2% of smartwatches include a gyroscope.
Cadence sensor
yes
Cadence sensor
yes
â–² Better than 69% of models
This smartwatch includes a cadence sensor. 69% of smartwatches include a cadence sensor.
Cadence may require external sensor/app pairing on some models.
Distance tracking
yes
Distance tracking
yes
â–² Better than 4% of models
This smartwatch supports distance tracking. 4.1% of smartwatches support distance tracking.
Show more
What reviewers say
Battery life
0.75 days
Battery life
0.75 days
â–¼ Worse than 98% of models
Market range: <1 days – >16 days
This smartwatch offers a battery life of 0.75 days which is shorter than that of 98% of smartwatches and equal to that of 2% of smartwatches.
Battery life in training mode
5.5 h
Battery life in training mode
5.5 h
â–¼ Worse than 90% of models
Market range: <5.5 h – >48 h
This smartwatch lasts 5.5 h in training mode which is shorter than 89.8% of smartwatches and equal to that of 0.5% of smartwatches.
Battery life with GPS on
6 h
Battery life with GPS on
6 h
â–¼ Worse than 87% of models
Market range: <5.75 h – >43 h
This smartwatch lasts 6 h with GPS on which is shorter than 87% of smartwatches and equal to that of 2.8% of smartwatches.
Battery power
258 mAh
Battery power
258 mAh
â–¼ Worse than 69% of models
Market range: <195 mAh – >475 mAh
This smartwatch has a battery capacity of 258 mAh which is smaller than the batteries in 69.2% of smartwatches.
Charge time
120 min
Charge time
120 min
â–¼ Worse than 43% of models
Market range: <60 min – >150 min
This smartwatch charges in 120 min which is faster than 13.1% of smartwatches and equal to the charge time of 44.2% of smartwatches.
Show more
What reviewers say
Operating system
watchOS
Operating system
watchOS
★ Better than 96% of models
This smartwatch runs watchOS which is more advanced than the operating system in 95.7% of smartwatches and the same as that in 4.3% of smartwatches.
OS detail: watchOS (10.6).
Software update frequency
ended
Software update frequency
ended
â–¼ Worse than 43% of models
This smartwatch has ended software update support which is less active than that of 42.6% of smartwatches and equal to that of 57.5% of smartwatches.
Third-party app support
yes
Third-party app support
yes
â–² Better than 52% of models
This smartwatch supports third-party apps. 52.4% of smartwatches support third-party apps.
Notifications
yes
Notifications
yes
Category Benchmark
This smartwatch supports notifications. 0.3% of smartwatches support notifications.
Voice assistant support
yes
Voice assistant support
yes
â–² Better than 32% of models
This smartwatch supports voice assistants. 32.4% of smartwatches support voice assistants.
Show more
What reviewers say
Cellular module
yes
Cellular module
yes
â–² Better than 82% of models
This smartwatch includes a cellular module. 82.2% of smartwatches include a cellular module.
Cellular support may depend on LTE/GPS+Cellular variant selection.
SIM cards
1
SIM cards
1
â–² Better than 2% of models
Market range: <0 – >5
This smartwatch uses 1 for cellular connectivity which is more advanced than that of 2% of smartwatches and the same as that of 98% of smartwatches.
eSIM on cellular models only.
GPS
yes
GPS
yes
â–² Better than 44% of models
This smartwatch supports GPS. 43.9% of smartwatches support GPS.
Galileo support
yes
Galileo support
yes
â–² Better than 62% of models
This smartwatch supports Galileo navigation. 61.6% of smartwatches support Galileo navigation.
Compass
no
Compass
no
â–¼ Worse than 53% of models
This smartwatch does not include a compass. 52.7% of smartwatches include a compass.
Show more
What reviewers say
Screen size
1.57 inch
Screen size
1.57 inch
â–² Better than 73% of models
Market range: <1.2 inch – >1.82 inch
This smartwatch has a screen size of 1.57 inch which is larger than the screens of 72.7% of smartwatches and equal to those of 1.2% of smartwatches.
Some sources mention multiple/uncertain size variants.
Display type
OLED
Display type
OLED
â–¼ Worse than 50% of models
This smartwatch uses a OLED display type which is less advanced than that of 50.3% of smartwatches and the same as that of 9.6% of smartwatches.
Retina branding. LTPO panel wording.
Resolution
324x 394
Resolution
324x 394
â–¼ Worse than 53% of models
This smartwatch has a display resolution of 324x394 which is lower than that of 52.7% of smartwatches and equal to that of 0.7% of smartwatches.
Pixel density
325 ppi
Pixel density
325 ppi
â–¼ Worse than 54% of models
Market range: <207 ppi – >461 ppi
This smartwatch has a pixel density of 325 ppi which is lower than that of 53.9% of smartwatches and equal to that of 1% of smartwatches.
Display brightness
1,000 nits
Display brightness
1,000 nits
â–² Better than 59% of models
Market range: <450 nits – >2k nits
This smartwatch reaches 1,000 nits of display brightness, which is higher than that of 59.4% of smartwatches and equal to that of 26.5% of smartwatches.
Show more
What reviewers say
CPU speed
2x 1.5 GHz
CPU speed
2x 1.5 GHz
â–² Better than 77% of models
This smartwatch uses a CPU configuration of 2x1.5 GHz which is faster than that in 77.2% of smartwatches and equal to that in 1.2% of smartwatches.
Processor model
Apple S4
Processor model
Apple S4
★ Better than 91% of models
This smartwatch uses the Apple S4 processor model.
RAM
1 GB
RAM
1 GB
â–² Better than 31% of models
Market range: <0.5 GB – >2 GB
This smartwatch has 1 GB of RAM which is larger than the RAM in 31.3% of smartwatches and equal to that of 45.8% of smartwatches.
Internal storage
16 GB
Internal storage
16 GB
â–² Better than 80% of models
Market range: <0 GB – >32 GB
This smartwatch uses 16 GB for internal storage which is larger than that of 79.8% of smartwatches and equal to that of 4.7% of smartwatches.
External memory slot
no
External memory slot
no
Category Benchmark
This smartwatch does not include an external memory slot. 0.3% of smartwatches include an external memory slot.
Show more
What reviewers say

Apple Watch Series 4 40mm vs the average smartwatch

246810TotalHealthFitnessBatteryConnectivityDisplay & DesignSmart featuresHardware
  • ECG support
    ECG
    yes
    â–² Better than 84% of models
    This smartwatch supports ECG, the average smartwatch does not. 16.6% of smartwatches support ECG.
  • More advanced operating system
    Operating system
    watchOS
    ★ Better than 96% of models
    This smartwatch runs a more advanced operating system than the average smartwatch (watchOS vs Proprietary OS).
    OS detail: watchOS (10.6).
    watchOS vs Proprietary OS
  • Built-in cellular module
    Cellular module
    yes
    â–² Better than 82% of models
    This smartwatch includes a cellular module, the average smartwatch does not. 17.9% of smartwatches include a cellular module.
    Cellular support may depend on LTE/GPS+Cellular variant selection.
  • Fall detection
    Fall detection
    yes
    â–² Better than 79% of models
    This smartwatch supports fall detection, the average smartwatch does not. 21.3% of smartwatches support fall detection.
  • HRV tracking
    HRV tracking
    yes
    â–² Better than 59% of models
    This smartwatch supports HRV tracking, the average smartwatch does not. 40.8% of smartwatches support HRV tracking.
  • Maps support
    Maps support
    yes
    â–² Better than 69% of models
    This smartwatch supports maps, the average smartwatch does not. 31.5% of smartwatches support maps.
  • VO2 max measurement
    VO2 max measurement
    yes
    â–² Better than 52% of models
    This smartwatch measures VO2 max, the average smartwatch does not. 47.6% of smartwatches measure VO2 max.
  • Emergency SOS
    Emergency SOS
    yes
    â–² Better than 57% of models
    This smartwatch includes Emergency SOS, the average smartwatch does not. 42.8% of smartwatches include Emergency SOS.
  • ECG support
    ECG
    yes
    â–² Better than 84% of models
    This smartwatch supports ECG, the average smartwatch does not. 16.6% of smartwatches support ECG.
  • HRV tracking
    HRV tracking
    yes
    â–² Better than 59% of models
    This smartwatch supports HRV tracking, the average smartwatch does not. 40.8% of smartwatches support HRV tracking.
  • VO2 max measurement
    VO2 max measurement
    yes
    â–² Better than 52% of models
    This smartwatch measures VO2 max, the average smartwatch does not. 47.6% of smartwatches measure VO2 max.
  • Irregular heart rate alerts
    Irregular heart rate warnings
    yes
    â–² Better than 52% of models
    This smartwatch supports irregular heart rate warnings, the average smartwatch does not. 48.1% of smartwatches support irregular heart rate warnings.
  • Weight tracking
    Weight tracking
    yes
    â–² Better than 61% of models
    This smartwatch supports weight tracking, the average smartwatch does not. 39.1% of smartwatches support weight tracking.
    Tracked through the companion app or smart-scale sync.
  • External heart rate monitor support
    External heart rate monitor compatibility
    yes
    â–² Better than 57% of models
    This smartwatch supports external heart rate monitor compatibility, the average smartwatch does not. 42.7% of smartwatches support external heart rate monitor compatibility.
  • Barometer sensor included
    Barometer
    yes
    â–² Better than 51% of models
    This smartwatch includes a barometer, the average smartwatch does not. 49.5% of smartwatches include a barometer.
  • Cadence tracking
    Cadence sensor
    yes
    â–² Better than 69% of models
    This smartwatch includes a cadence sensor, the average smartwatch does not. 31.1% of smartwatches include a cadence sensor.
    Cadence may require external sensor/app pairing on some models.
  • Route support
    Route support
    yes
    â–² Better than 50% of models
    This smartwatch supports route support, the average smartwatch does not. 50% of smartwatches support route support.
    Route support available via companion app.
  • Supports wireless charging
    Wireless charging
    yes
    â–² Better than 76% of models
    This smartwatch supports wireless charging, the average smartwatch does not. 24.5% of smartwatches support wireless charging.
    Wireless charging supported via proprietary charging puck/dock.
  • Built-in cellular module
    Cellular module
    yes
    â–² Better than 82% of models
    This smartwatch includes a cellular module, the average smartwatch does not. 17.9% of smartwatches include a cellular module.
    Cellular support may depend on LTE/GPS+Cellular variant selection.
  • Maps support
    Maps support
    yes
    â–² Better than 69% of models
    This smartwatch supports maps, the average smartwatch does not. 31.5% of smartwatches support maps.
  • NFC functionality
    NFC
    yes
    â–² Better than 57% of models
    This smartwatch supports NFC, the average smartwatch does not. 43.4% of smartwatches support NFC.
  • Supports Wi-Fi
    Wi-Fi support
    yes
    â–² Better than 57% of models
    This smartwatch supports Wi-Fi, the average smartwatch does not. 43.3% of smartwatches support Wi-Fi.
  • Galileo satellite support
    Galileo support
    yes
    â–² Better than 62% of models
    This smartwatch supports Galileo navigation, the average smartwatch does not. 38.5% of smartwatches support Galileo navigation.
  • 400 nits higher display brightness
    Display brightness
    1,000 nits
    â–² Better than 59% of models
    Market range: <450 nits – >2k nits
    This smartwatch has higher display brightness than the average smartwatch (1000 nits vs 600 nits). The average smartwatch reaches 600 nits.
    1,000 nits vs 600 nits
  • 14.9 g lighter weight
    Weight
    30.1 g
    â–² Better than 88% of models
    Market range: <29 g – >80 g
    This smartwatch is lighter than the average smartwatch (30.1 g vs 45 g). The average smartwatch weighs 45.0 g.
    30.1 g vs 45.0 g
  • Stronger display glass
    Display glass type
    Ion-X
    â–¼ Worse than 54% of models
    This smartwatch uses Ion-X display glass, while the average smartwatch uses mineral glass.
    Ion-X vs mineral glass
  • Better case material
    Case material
    aluminum, stainless steel
    â–² Better than 83% of models
    This smartwatch uses aluminum, stainless steel for the case material, while the average smartwatch uses polycarbonate.
    aluminum, stainless steel vs polycarbonate
  • 0.17 inch larger screen size
    Screen size
    1.57 inch
    â–² Better than 73% of models
    Market range: <1.2 inch – >1.82 inch
    This smartwatch has a larger screen size than the average smartwatch (1.6 inch vs 1.4 inch). The average smartwatch screen is 1.40 inch.
    Some sources mention multiple/uncertain size variants.
    1.57 inch vs 1.40 inch
  • 0.9 mm thinner watch body
    Thickness
    10.70 mm
    â–² Better than 75% of models
    Market range: <9.8 mm – >14.1 mm
    This smartwatch is thinner than the average smartwatch (10.7 mm vs 11.6 mm). The average smartwatch thickness is 11.6 mm.
    10.70 mm vs 11.6 mm
  • 8 mm narrower watch width
    Width
    34.0 mm
    ★ Better than 91% of models
    Market range: <34.6 mm – >46.8 mm
    This smartwatch is narrower than the average smartwatch (34 mm vs 42 mm). The average smartwatch width is 42.0 mm.
    34.0 mm vs 42.0 mm
  • 5 mm shorter watch height
    Height
    40.0 mm
    â–² Better than 88% of models
    Market range: <39.5 mm – >51 mm
    This smartwatch is shorter than the average smartwatch (40 mm vs 45 mm). The average smartwatch height is 45 mm.
    40.0 mm vs 45 mm
  • More advanced operating system
    Operating system
    watchOS
    ★ Better than 96% of models
    This smartwatch runs a more advanced operating system than the average smartwatch (watchOS vs Proprietary OS).
    OS detail: watchOS (10.6).
    watchOS vs Proprietary OS
  • Fall detection
    Fall detection
    yes
    â–² Better than 79% of models
    This smartwatch supports fall detection, the average smartwatch does not. 21.3% of smartwatches support fall detection.
  • Emergency SOS
    Emergency SOS
    yes
    â–² Better than 57% of models
    This smartwatch includes Emergency SOS, the average smartwatch does not. 42.8% of smartwatches include Emergency SOS.
  • Third-party app support
    Third-party app support
    yes
    â–² Better than 52% of models
    This smartwatch supports third-party apps, the average smartwatch does not. 47.6% of smartwatches support third-party apps.
  • 12 GB more storage
    Internal storage
    16 GB
    â–² Better than 80% of models
    Market range: <0 GB – >32 GB
    This smartwatch offers more internal storage than the average smartwatch (16 GB vs 4 GB). The average smartwatch provides 4 GB of storage.
    16 GB vs 4 GB
  • Faster CPU speed
    CPU speed
    2 x 1.5 GHz
    â–² Better than 77% of models
    This smartwatch uses a CPU configuration of 2x1.5 GHz, while the average smartwatch uses 1 GHz.
    2x1.5 GHz vs 1 GHz
  • More advanced processor model
    Processor model
    Apple S4
    ★ Better than 91% of models
    This smartwatch uses the Apple S4 processor model, while the average smartwatch uses Silicon Labs EFM32 Giant Gecko.
    Apple S4 vs Silicon Labs EFM32 Giant Gecko
  • No blood oxygen monitoring
    Blood oxygen monitoring
    no
    â–¼ Worse than 67% of models
    This smartwatch does not support blood oxygen monitoring, the average smartwatch does. 66.7% of smartwatches support blood oxygen monitoring.
  • No stress monitoring
    Stress monitoring
    no
    â–¼ Worse than 66% of models
    This smartwatch does not support stress monitoring, the average smartwatch does. 65.4% of smartwatches support stress monitoring.
  • 6.25 days day/s shorter battery life
    Battery life
    0.75 days
    â–¼ Worse than 98% of models
    Market range: <1 days – >16 days
    This smartwatch offers 0.8 days of battery life, while the average smartwatch offers 7 days.
    0.75 days vs 7 days
  • 14 h shorter GPS battery life
    Battery life with GPS on
    6 h
    â–¼ Worse than 87% of models
    Market range: <5.75 h – >43 h
    This smartwatch lasts less with GPS on than the average smartwatch (6 h vs 20 h). The average smartwatch lasts 20 h.
    6 h vs 20 h
  • No always-on display
    Always-On Display
    no
    â–¼ Worse than 68% of models
    This smartwatch does not have an always-on display, the average smartwatch does. 67.6% of smartwatches have an always-on display.
  • 13.75 h shorter training battery life
    Battery life in training mode
    5.5 h
    â–¼ Worse than 90% of models
    Market range: <5.5 h – >48 h
    This smartwatch lasts less in training mode than the average smartwatch (5.5 h vs 19.25 h). The average smartwatch lasts 19.25 h.
    5.5 h vs 19.25 h
  • No compass
    Compass
    no
    â–¼ Worse than 53% of models
    This smartwatch does not include a compass, the average smartwatch does. 52.6% of smartwatches include a compass.
  • Not compatible with Android
    Android compatibility
    no
    â–¼ Worse than 95% of models
    This smartwatch is not compatible with Android, the average smartwatch is. 95.3% of smartwatches are compatible with Android.
  • No blood oxygen monitoring
    Blood oxygen monitoring
    no
    â–¼ Worse than 67% of models
    This smartwatch does not support blood oxygen monitoring, the average smartwatch does. 66.7% of smartwatches support blood oxygen monitoring.
  • No stress monitoring
    Stress monitoring
    no
    â–¼ Worse than 66% of models
    This smartwatch does not support stress monitoring, the average smartwatch does. 65.4% of smartwatches support stress monitoring.
  • 5,534 m lower max altitude
    Maximum altitude
    3,000 m
    â–¼ Worse than 59% of models
    Market range: <3k m – >9.1k m
    This smartwatch supports a lower maximum altitude than the average smartwatch (3000 m vs 8534 m). The average smartwatch reaches 8534 m.
    3,000 m vs 8,534 m
  • 6.25 days day/s shorter battery life
    Battery life
    0.75 days
    â–¼ Worse than 98% of models
    Market range: <1 days – >16 days
    This smartwatch offers 0.8 days of battery life, while the average smartwatch offers 7 days.
    0.75 days vs 7 days
  • 14 h shorter GPS battery life
    Battery life with GPS on
    6 h
    â–¼ Worse than 87% of models
    Market range: <5.75 h – >43 h
    This smartwatch lasts less with GPS on than the average smartwatch (6 h vs 20 h). The average smartwatch lasts 20 h.
    6 h vs 20 h
  • 13.75 h shorter training battery life
    Battery life in training mode
    5.5 h
    â–¼ Worse than 90% of models
    Market range: <5.5 h – >48 h
    This smartwatch lasts less in training mode than the average smartwatch (5.5 h vs 19.25 h). The average smartwatch lasts 19.25 h.
    5.5 h vs 19.25 h
  • Basic battery type
    Battery type
    Li-ion
    â–¼ Worse than 51% of models
    This smartwatch uses a Li-ion battery, while the average smartwatch uses Li-Po.
    Li-ion vs Li-Po
  • 42 mAh smaller battery capacity
    Battery life
    258 mAh days
    â–¼ Worse than 98% of models
    Market range: <1 days – >16 days
    This smartwatch has a smaller battery capacity than the average smartwatch (258 mAh vs 300 mAh). The average smartwatch battery is 300 mAh.
    258 mAh vs 300 mAh
  • No compass
    Compass
    no
    â–¼ Worse than 53% of models
    This smartwatch does not include a compass, the average smartwatch does. 52.6% of smartwatches include a compass.
  • Not compatible with Android
    Android compatibility
    no
    â–¼ Worse than 95% of models
    This smartwatch is not compatible with Android, the average smartwatch is. 95.3% of smartwatches are compatible with Android.
  • No always-on display
    Always-On Display
    no
    â–¼ Worse than 68% of models
    This smartwatch does not have an always-on display, the average smartwatch does. 67.6% of smartwatches have an always-on display.
  • Basic display type
    Display type
    OLED
    â–¼ Worse than 50% of models
    This smartwatch uses OLED display technology, while the average smartwatch features AMOLED.
    Retina branding. LTPO panel wording.
    OLED vs AMOLED
  • Less practical form
    Form
    rectangular
    â–¼ Worse than 72% of models
    This smartwatch uses a rectangular form, while the average smartwatch uses round.
    rectangular vs round
  • 10 °C lower max temperature
    Maximum operating temperature
    35.0 °C
    â–¼ Worse than 82% of models
    Market range: <35 °C – >60 °C
    This smartwatch handles a lower maximum operating temperature than the average smartwatch (35 °C vs 45 °C). The average smartwatch reaches 45.0 °C.
    35.0 °C vs 45.0 °C
  • No smart alarm
    Smart alarm
    no
    â–¼ Worse than 53% of models
    This smartwatch does not support a smart alarm, the average smartwatch does. 52.7% of smartwatches support smart alarms.
  • 3 year/s older release date
    Release date
    2018
    â–¼ Worse than 79% of models
    Market range: <2k – >2k
    This smartwatch is an older model than the average smartwatch (2018 vs 2021). The average smartwatch was released in 2021.
    September 2018
    2018 vs 2021

Video reviews

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

9.0
Mark's Tech Vlogs
≈ estimated
11/04/2019
Hands-on review · fitness, apps and daily use
Verdict
Apple Watch Series 4 40mm is a strong redesign of an already excellent watch, with faster performance and solid fitness tracking.
8.0
Digital Trends
≈ estimated
14/09/2018
First look · hands-on impressions and new features
Verdict
Apple Watch Series 4 40mm feels great with haptic crown feedback and detailed faces, but full testing is still to come.
Not graded yet
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What reviewers agree on

Based on 10 · 13

Reviewers love the display, controls and fitness tracking, but battery life is short and some features aren't available everywhere.
Praised
Mixed views
Criticised
Pick a topic to see who said what

Expert reviews

In-depth analysis and verdict from leading tech publications

9.0
tomsguide.com
✓ explicit
17/09/2021
Review · Heart and fall sensors
Verdict
The Apple Watch Series 4 suits people who want heart-rhythm and fall alerts with a much larger screen, though newer models have overtaken it.
7.0
choose.co.uk
≈ estimated
10/08/2022
Hands-on review · Easy setup
Verdict
The Apple Watch Series 4 is easy to set up and light to wear, with a bigger screen and automatic workout detection, but it doesn't track sleep.
9.0
techradar.com
✓ explicit
07/06/2021
Review · Heart health features
Verdict
The Apple Watch Series 4 is a bigger-screened upgrade over the Series 3, with heart features suited to people with health needs, though it needs charging daily.
8.0
cyclist.co.uk
✓ explicit
12/05/2019
Review · Cycling and GPS
Verdict
The Apple Watch Series 4 suits cyclists wanting an everyday watch for rides, though it won't pair with power meters and some ride data won't reach Strava.
9.0
trustedreviews.com
✓ explicit
01/04/2019
Review · Design and straps
Verdict
The Apple Watch Series 4 suits buyers who want a large, easy-to-wear screen and plenty of straps, but it needs nightly charging and lacks an always-on display.
9.0
thesweetsetup.com
≈ estimated
16/10/2018
Design review · Gold finish
Verdict
The Apple Watch Series 4 looks most like a real watch with softer corners and a gold stainless steel finish, though older bands fit less precisely.
8.0
irishtimes.com
✓ explicit
04/10/2018
Hands-on review · Safety features
Verdict
The Apple Watch Series 4 is Apple's best yet, with useful fall and heart alerts for older relatives, but its battery lasts only about a day and a half.
9.0
techadvisor.com
✓ explicit
01/10/2018
Early review · Bigger screen
Verdict
The Apple Watch Series 4 is a strong wearable with a much bigger screen and haptic crown, but wait for ECG if that's your main reason to buy.
stuff.tv
25/09/2018
Not graded yet
huffingtonpost.co.uk
24/09/2018
Not graded yet
wareable.com
19/09/2018
Not graded yet
zeipad.com
01/09/2018
Not graded yet
wired.com
19/09/2018
Not graded yet
9.0
techgearlab.com
≈ estimated
09/11/2018
Lab test · Fitness accuracy
Verdict
The Apple Watch Series 4 suits iPhone owners who want a fast, intuitive, accurate watch, but its battery lasts only about two days in light use.
watchgeneration.fr
28/09/2018
Not graded yet
sport-passion.fr
25/09/2018
Not graded yet
numerama.com
25/09/2018
Not graded yet
01net.com
26/09/2018
Not graded yet
8.0
mac4ever.com
✓ explicit
12/10/2018
Hands-on test · Screen size
Verdict
The Apple Watch Series 4 is a clear step up in screen size and crown feel, but its fall detection isn't convincing enough yet for older relatives.

Third-party reviews

Read buyer reviews on Amazon →

What we like about Apple Watch Series 4 40mm

  • Larger, edge-to-edge display (30% more screen area)
  • Thinner, more comfortable casing compared to Series 3
  • Advanced health features: FDA-cleared ECG and Fall Detection
  • Significant speed boost with the S4 dual-core processor
  • Louder speaker (50% increase) and improved microphone placement for calls
  • Haptic feedback added to the Digital Crown for a more tactile feel
  • Backward compatibility with all previous Apple Watch bands

What we don't like about Apple Watch Series 4 40mm

  • Battery life remains limited to approximately 18 hours or 1-2 days
  • No always-on display (users must raise wrist to see time)
  • Lack of native sleep tracking due to daily charging requirements
  • Higher starting price compared to previous models
  • Limited first-party watch face customisation options
  • Smaller 40mm targets can be difficult for some users to tap accurately
  • Requires an iPhone for full functionality and initial setup

Verdict

The Apple Watch Series 4 40mm features a redesigned LTPO OLED Retina display with a resolution of 324x394 pixels, offering roughly 30% more screen area than previous generations within a thinner 10.7mm casing. Powered by the dual-core 64-bit S4 processor for up to twice the speed of its predecessor, it integrates advanced health sensors including an FDA-cleared electrical heart sensor for ECGs, a second-generation optical heart sensor, and an improved accelerometer and gyroscope capable of fall detection. Key advantages include its larger, nearly frameless screen, water resistance up to 50 metres, and life-saving features like low heart rate notifications and emergency SOS. However, it lacks an always-on display found in newer models, provides a consistent but limited 18-hour battery life that rarely exceeds one day of heavy use, and is compatible only with iPhone devices.

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