Samsung · 2021
Galaxy Watch 4 Wi-Fi 40mm Size, Dimensions & Wrist Fit
Case Width
40.4mm
Thickness
9.8mm
Lug-to-Lug
39.3mm
Weight
25.9g
The Galaxy Watch 4 Wi-Fi 40mm looks in proportion on wrists of 13–17.5 cm (5.1–6.9 in) round, and fills the wrist at 13–14.5 cm (39.3mm lug to lug).
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Does the Galaxy Watch 4 Wi-Fi 40mm fit your wrist?
The 40mm suits wrists of about 13–17.5 cm round; the 44mm, 13.5–19 cm. Both work from 13.5 to 17.5 cm, where it is a choice between more skin either side (the 40mm) and a case that fills the wrist (the 44mm). Under 13.5 cm only the 40mm's lugs stay on the wrist; over 17.5 cm the 40mm starts to look small.
| Wrist round (mm left each side) | 40mm | 44mm |
|---|---|---|
| 14 cm / 5.5 in | Sweet spot (2.9mm) | Bold (0.9mm) |
| 15 cm / 5.9 in | Balanced (4.5mm) | Sweet spot (2.5mm) |
| 16 cm / 6.3 in | Balanced (6.2mm) | Balanced (4.2mm) |
| 17 cm / 6.7 in | Balanced (7.8mm) | Balanced (5.8mm) |
| 18 cm / 7.1 in | Understated (9.4mm) | Balanced (7.4mm) |
| 19 cm / 7.5 in | Understated (11mm) | Balanced (9mm) |
| 20 cm / 7.9 in | Understated (12.6mm) | Understated (10.6mm) |
Which Galaxy Watch 4 size fits you?
40mmViewing
40.4mm · 9.8mm thick · 25.9g
44mm
44.4mm · 9.8mm thick · 30.3g
View this sizeThe Galaxy Watch 4 Wi-Fi 40mm in short
- The 44mm version is 4mm wider and 4.4g heavier.
- Compared with the previous Galaxy Watch3 Wi-Fi 41mm, it is 0.6mm narrower, 1.5mm thinner and 22.3g lighter.
- Replaced by the Galaxy Watch5 Wi-Fi 40mm, which is 2.9mm wider and 2.8g heavier.
- At 9.8mm, the 3rd thinnest of the 9 Samsung watches 39–41mm across.
- 25.9g on the wrist. Lighter than 97% of the 38 smartwatches 40mm across that we have weights for.
Compare the Galaxy Watch 4 Wi-Fi 40mm head to head
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Galaxy Watch 4 Wi-Fi 40mm battery life
Published runtime
- Battery life2 days
Charges in 2 hours
Where it ranks among Samsung watches
- Everyday use2 days#22 of 64
- Power save40 hours#10 of 11
- Capacity247 mAh#54 of 64
2D Dimension Schematics
- Samsung Galaxy Watch 4 Wi-Fi 40mm 40.4mm × 39.3mm · 9.8mm thick
3D preview
Samsung Galaxy Watch 4 Wi-Fi 40mm on a wrist
What size band does the Galaxy Watch 4 Wi-Fi 40mm take?
Lug width
20mm
Alternatives to the Galaxy Watch 4 Wi-Fi 40mm
Galaxy Watch 4 Wi-Fi 40mm — Frequently Asked Questions
Is the Samsung Galaxy Watch 4 Wi-Fi 40mm thick for a 40mm watch?
At 9.8mm, thinner than 87% of the 40 smartwatches 40mm across that we track, so it slides under a cuff more easily than most of its size.
Galaxy Watch 4 Wi-Fi 40mm specifications
- Battery life
- 2 days
- Display
- 1.2 inches
- Resolution
- 396 x 396 px
- Water rating
- 5 ATM
- Glass
- Gorilla Glass DX+
- Strap
- 20 mm
- Storage
- 16GB
- Charging
- 2 hours
Show all specificationsSamsung's published specification, for reference · checked September 2026
Design
- width
- 40.4
- height
- 39.3
- volume
- 15.56 cm³
- weight
- 25.9 g
- thickness
- 9.8
- ATM rating
- 5 ATM
- resolution
- 396 x 396 px
- screen size
- 1.2 inches
- Display type
- OLED/AMOLED
- Has a display
- Yes
- pixel density
- 455 ppi
- width of band
- 20 mm
- water resistance
- Waterproof
- Always-On Display
- Yes
- has a touch screen
- Yes
- Gorilla Glass version
- Gorilla Glass DX+
- waterproof depth rating
- 50 m
- Watch band is replaceable
- Yes
- Has sapphire glass display
- No
- Ingress Protection (IP) rating
- IP68
- has branded damage-resistant glass
- Yes
Battery
- charge time
- 2 hours
- battery life
- 2 days
- battery power
- 247 mAh
- has wireless charging
- Yes
- has a removable battery
- No
- Has a solar power battery
- No
- has a rechargeable battery
- Yes
- battery life in power save mode
- 40 hours
Sensors
- has GPS
- Yes
- has a compass
- Yes
- Has a barometer
- Yes
- has a gyroscope
- Yes
- Has a cadence sensor
- No
- has an accelerometer
- Yes
- Monitors perspiration
- No
- Has a heart rate monitor
- Yes
- Has a temperature sensor
- No
- Monitors blood oxygenation levels
- Yes
Features
- RAM
- 1.5GB
- CPU speed
- 2 x 1.18 GHz
- release date
- 2021-08-11
- Has a stopwatch
- Yes
- Has smart alarm
- No
- warranty period
- 1 years
- Has call control
- Yes
- Has silent alarm
- Yes
- has HRV tracking
- Yes
- internal storage
- 16GB
- measures VO2 max
- Yes
- Has notifications
- Yes
- Has ECG technology
- Yes
- Locates your phone
- Yes
- has a front camera
- No
- has fall detection
- Yes
- has voice commands
- Yes
- Acquires GPS faster
- No
- Has vibrating alerts
- Yes
- number of microphones
- 1
- shows readiness level
- No
- Can be used to answer calls
- Yes
- measures resting heart rate
- Yes
- has irregular heart rate warnings
- Yes
- has fast/slow heart rate notifications
- Yes
- Has a built-in camera remote control function
- Yes
Connectivity
- has NFC
- Yes
- Wi-Fi version
- Wi-Fi 4 (802.11n)
- supports ANT+
- No
- supports Wi-Fi
- Yes
- supports Galileo
- Yes
- Bluetooth version
- 5
- has a cellular module
- No
- Is compatible with iOS
- No
- Is compatible with Android
- Yes
Miscellaneous
- has aptX
- No
- Has passcode
- Yes
- Has auto pause
- Yes
- Is compatible with Windows
- No
- Is compatible with Mac OS X
- No
- has an ambient light sensor
- Yes
- has an external memory slot
- No
- Compatible with smart scales
- Yes
- has a battery level indicator
- Yes
- has a socket for a 3.5 mm audio jack
- No
- Compatible with external heart rate monitors
- Yes
App & Software
- Ad-free
- Yes
- Free app
- Yes
- Tracks BMI
- Yes
- Has coaching
- Yes
- Supports routes
- Yes
- Has achievements
- Yes
- Has goal setting
- Yes
- Has exercise diary
- Yes
- Has weight tracking
- Yes
- Predicts start date
- Yes
- Tracks water intake
- Yes
- Has inactivity alerts
- Yes
- Has period notifications
- Yes
- Has temperature tracking
- No
- Doesn’t require account
- No
- Provides activity reports
- Yes
- Counts how many calories you've burned
- Yes
Activity tracking
- Measures pace
- Yes
- Tracks distance
- Yes
- Tracks elevation
- Yes
- Designed for golf
- No
- Tracks your sleep
- Yes
- Tracks steps taken
- Yes
- Designed for diving
- No
- Has a route tracker
- Yes
- Has exercise tagging
- Yes
- Has multi-sport mode
- Yes
- Tracks calorie intake
- Yes
- Provides sleep reports
- Yes
- Detects activities automatically
- Yes
- Has a stroke counter for swimming
- Yes
