Samsung Galaxy Watch8 LTE 40mm vs Xiaomi Watch S4 41mm
Size, specs & wrist fit compared
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Which one fits you
On wrists narrower than about 45mm, the Xiaomi Watch S4 41mm is the safer pick — it stays proportionate down to roughly 43mm, where the Samsung Galaxy Watch8 LTE 40mm starts to hang over the edge. Above 45mm both sit cleanly, and the Samsung Galaxy Watch8 LTE 40mm gives you more presence.
The Xiaomi Watch S4 41mm wears larger than the Samsung Galaxy Watch8 LTE 40mm (41.2mm vs 40.4mm case), giving it more wrist presence — and needing a wider wrist to sit cleanly.
The Samsung Galaxy Watch8 LTE 40mm is the slimmer of the two (8.6mm vs 9.5mm), so it slides under a cuff more easily.
On the wrist the Samsung Galaxy Watch8 LTE 40mm feels lighter (30g vs 32g, case only).
The Samsung Galaxy Watch8 LTE 40mm is thinner than 83% of the 40mm watches we track and the Xiaomi Watch S4 41mm than 98% of the 41mm ones — so both wear flatter than their widths suggest.
The Xiaomi Watch S4 41mm is 0.8mm wider, 1.5mm shorter, 0.9mm thicker and 2g heavier than the Samsung Galaxy Watch8 LTE 40mm. Both are circular.
Samsung
Galaxy Watch8 - LTE · 40mm
Xiaomi
Watch S4 41mm
Switch or add watches
Samsung
Galaxy Watch8 - LTE · 40mm
Xiaomi
Watch S4 41mm
Watch Fit Tool
For sports watches, lug-to-lug (L2L) is what matters most — it decides whether a watch overhangs your wrist. Bulky is fine; overhang is not.
Measure at the point where you wear your watch — typically just below the wrist bone.
Flat width — lay your arm on a table, palm facing up, and measure straight across the top of your wrist with a ruler. Bone to bone; do not follow the curve down the sides.
Around — wrap a tape measure snugly round the wrist. No tape? Wrap a strip of paper, mark the overlap and hold the strip against a ruler.
Width ≠ circumference. They are different numbers — around 170mm is about 64mm across — so set the toggle to whichever one you actually measured before you type it in.
Samsung Galaxy Watch8 - LTE · 40mm
Case 40.4mm · Lug-to-lug 42.7mm · Thickness 8.6mm · 30g
Balanced Fit
42.7mm on a 55mm wrist
Comfortably inside the edges of your wrist, and it seats and sits low enough to wear without thinking about it.
On a 55mm wrist the sweet spot is 47–53mm lug to lug. This one is 42.7mm, so you could go bigger.
Measure where you wear it, just below the wrist bone. Either of these works — the tool converts between them.
- 1. Flat width — arm flat on a table, palm up. Measure straight across the top of the wrist, bone to bone, ignoring the curve down the sides.
- 2. Around — a tape, or a strip of paper marked and held against a ruler, snug the whole way round.
Leather: Attaches at the lugs, so the case back rests on your skin. Thins and softens with wear. Typical figures, not this model’s own.
Show the measurementsHide the measurements
- Across the wrist6.1mm spare each side
Comfortable, with visible skin either side.
- Off the wrist8.6mm off the skin
Sits low enough to disappear under a cuff. (8.6mm case, back against the skin)
- How it seats~3.5mm under the rim
Seats well, with the case back following most of the wrist.
- Weight on the wrist30g
Light enough to forget you have it on. (0.5g per mm of wrist)
Xiaomi Watch S4 41mm
Case 41.2mm · Lug-to-lug 41.2mm · Thickness 9.5mm · 32g
Balanced Fit
41.2mm on a 55mm wrist
Comfortably inside the edges of your wrist, and it seats and sits low enough to wear without thinking about it.
On a 55mm wrist the sweet spot is 47–53mm lug to lug. This one is 41.2mm, so you could go bigger.
Measure where you wear it, just below the wrist bone. Either of these works — the tool converts between them.
- 1. Flat width — arm flat on a table, palm up. Measure straight across the top of the wrist, bone to bone, ignoring the curve down the sides.
- 2. Around — a tape, or a strip of paper marked and held against a ruler, snug the whole way round.
Leather: Attaches at the lugs, so the case back rests on your skin. Thins and softens with wear. Typical figures, not this model’s own.
Show the measurementsHide the measurements
- Across the wrist6.9mm spare each side
Comfortable, with visible skin either side.
- Off the wrist9.5mm off the skin
Sits low enough to disappear under a cuff. (9.5mm case, back against the skin)
- How it seats~3.8mm under the rim
Seats well, with the case back following most of the wrist.
- Weight on the wrist32g
Light enough to forget you have it on. (0.6g per mm of wrist)
2D Dimension Schematics
Every case drawn to scale on a shared centre — from above, and in profile against the wrist.
- Samsung Galaxy Watch8 - LTE · 40mm40.4mm × 42.7mm · 8.6mm thick
- Xiaomi Watch S4 41mm41.2mm · 9.5mm thick
3D preview
Samsung Galaxy Watch8 - LTE · 40mm vs Xiaomi Watch S4 41mm on a wrist
Sized to your own wrist, turned any way you like.
Shapes are built from published measurements, not manufacturer 3D models — accurate proportions, generic dial.
Battery life compared
Furthest apart in Smartwatch mode, where the Xiaomi Watch S4 41mm lasts 4.0× as long as the Samsung Galaxy Watch8 LTE 40mm (8 days against 2 days).
Samsung Galaxy Watch8 LTE 40mmXiaomi Watch S4 41mm
Smartwatch
2 days8 days
Specifications
The short version
11 key specs| Spec | SamsungGalaxy Watch8 - LTE · 40mm | XiaomiWatch S4 41mm |
|---|---|---|
| Case Width | 40.4mm | 41.2mm |
| Lug-to-Lug | 42.7mm | 41.2mm |
| Thickness | 8.6mm | 9.5mm |
| Weight | 30g | 32g |
| Shape | Circular | Circular |
| Water Resistance | 5 ATM | 5 ATM |
| GPS | Yes | Yes |
| Display type | OLED/AMOLED | OLED/AMOLED |
| Screen size | 1.34 inches | 1.32 inches |
| Battery life | 2 days | 8 days |
| Released | 2025 | 2025 |
Every specification
117 specs| Spec | Samsung Galaxy Watch8 - LTE · 40mm | Xiaomi Watch S4 41mm |
|---|---|---|
| Design | ||
| width | 40.4 | 41.2 |
| height | 42.7 | 41.2 |
| volume | 14.84 cm³ | 16.13 cm³ |
| weight | 30 g | 32 g |
| thickness | 8.6 | 9.5 |
| ATM rating | 5 ATM | 5 ATM |
| resolution | 438 x 438 px | 466 x 466 px |
| screen size | 1.34 inches | 1.32 inches |
| Display type | OLED/AMOLED | OLED/AMOLED |
| Has a display | Yes | Yes |
| pixel density | 327 ppi | 320 ppi |
| width of band | 20 mm | — |
| water resistance | Water resistant | Waterproof |
| Always-On Display | Yes | Yes |
| has a touch screen | Yes | Yes |
| is designed for kids | No | No |
| waterproof depth rating | 50 m | — |
| Watch band is replaceable | Yes | Yes |
| Has sapphire glass display | Yes | Yes |
| maximum operating temperature | 35 °C | — |
| Ingress Protection (IP) rating | IP68 | — |
| has branded damage-resistant glass | No | No |
| lowest potential operating temperature | 0 °C | — |
| Battery | ||
| battery life | 2 days | 8 days |
| battery power | 325 mAh | 320 mAh |
| has wireless charging | Yes | No |
| has a removable battery | No | No |
| Has a solar power battery | No | No |
| has a rechargeable battery | Yes | Yes |
| Sensors | ||
| has GPS | Yes | Yes |
| has a compass | Yes | Yes |
| Has a barometer | Yes | Yes |
| has a gyroscope | Yes | Yes |
| Has a cadence sensor | No | No |
| has an accelerometer | Yes | Yes |
| Monitors perspiration | No | No |
| Has a heart rate monitor | Yes | Yes |
| Has a temperature sensor | Yes | Yes |
| Monitors blood oxygenation levels | Yes | Yes |
| Features | ||
| RAM | 2GB | — |
| release date | 2025-07-09 | 2025-06-26 |
| Has a stopwatch | Yes | Yes |
| Has smart alarm | No | No |
| Has call control | Yes | Yes |
| Has silent alarm | Yes | Yes |
| has HRV tracking | Yes | Yes |
| internal storage | 32GB | 32GB |
| measures VO2 max | Yes | Yes |
| Has notifications | Yes | Yes |
| Has ECG technology | Yes | No |
| Locates your phone | Yes | Yes |
| has fall detection | Yes | Yes |
| has voice commands | Yes | Yes |
| Acquires GPS faster | Yes | Yes |
| Has vibrating alerts | Yes | Yes |
| shows readiness level | Yes | Yes |
| Can be used to answer calls | Yes | Yes |
| measures resting heart rate | Yes | Yes |
| has irregular heart rate warnings | Yes | No |
| has fast/slow heart rate notifications | Yes | Yes |
| Has a built-in camera remote control function | Yes | Yes |
| warranty period | — | 1 years |
| has a front camera | — | No |
| number of microphones | — | 1 |
| Connectivity | ||
| has NFC | Yes | Yes |
| SIM cards | 1 eSIM | 1 eSIM |
| Wi-Fi version | Wi-Fi 4 (802.11n) | — |
| supports ANT+ | No | No |
| supports Wi-Fi | Yes | No |
| supports Galileo | Yes | Yes |
| Bluetooth version | 5.3 | 5.4 |
| has a cellular module | Yes | Yes |
| Is compatible with iOS | No | Yes |
| Is compatible with Android | Yes | Yes |
| Miscellaneous | ||
| Has passcode | Yes | Yes |
| Has auto pause | Yes | — |
| Is compatible with Windows | No | No |
| Is compatible with Mac OS X | No | No |
| has an external memory slot | No | No |
| Compatible with smart scales | Yes | — |
| has a battery level indicator | Yes | Yes |
| has a socket for a 3.5 mm audio jack | No | No |
| Compatible with external heart rate monitors | Yes | — |
| App & Software | ||
| Ad-free | Yes | Yes |
| Free app | Yes | Yes |
| Tracks BMI | Yes | — |
| Has coaching | Yes | No |
| Includes maps | Yes | Yes |
| Supports routes | Yes | No |
| Has achievements | Yes | Yes |
| Has goal setting | Yes | Yes |
| Has exercise diary | Yes | Yes |
| Can be personalised | Yes | Yes |
| Has weight tracking | Yes | Yes |
| Predicts start date | Yes | Yes |
| Tracks water intake | Yes | Yes |
| Has inactivity alerts | Yes | Yes |
| Has period notifications | Yes | Yes |
| Has temperature tracking | Yes | Yes |
| Provides activity reports | Yes | Yes |
| Counts how many calories you've burned | Yes | Yes |
| Predicts ovulation | — | Yes |
| Doesn’t require account | — | No |
| Activity tracking | ||
| Measures pace | Yes | Yes |
| Tracks distance | Yes | Yes |
| Tracks elevation | Yes | Yes |
| Designed for golf | No | — |
| Tracks your sleep | Yes | Yes |
| Tracks steps taken | Yes | Yes |
| Designed for diving | No | No |
| Has a route tracker | Yes | Yes |
| Has exercise tagging | Yes | Yes |
| Has multi-sport mode | No | — |
| Tracks calorie intake | Yes | Yes |
| Provides sleep reports | Yes | Yes |
| Detects activities automatically | Yes | Yes |
| Has a stroke counter for swimming | Yes | Yes |
Wrist Fit
Samsung Galaxy Watch8 LTE 40mm
Sits best on wrists ~45–61mm wide (≈ 12.0–16.3cm circumference).
Xiaomi Watch S4 41mm
Sits best on wrists ~43–59mm wide (≈ 11.5–15.8cm circumference).
Frequently Asked Questions
Is the Samsung Galaxy Watch8 LTE 40mm bigger than the Xiaomi Watch S4 41mm?
The Xiaomi Watch S4 41mm is bigger — 41.2mm vs 40.4mm case width.
Which fits a smaller wrist better, the Samsung Galaxy Watch8 LTE 40mm or the Xiaomi Watch S4 41mm?
The Samsung Galaxy Watch8 LTE 40mm suits wrists around 45–61mm wide, and the Xiaomi Watch S4 41mm around 43–59mm. The one with the smaller lower bound is the safer pick for a small wrist.
Can I see the Samsung Galaxy Watch8 LTE 40mm and Xiaomi Watch S4 41mm side by side at true scale?
Yes — the schematics and photos above show both watches at matched scale, and our fit tool overlays each on your wrist width.