Apple Watch Ultra 3 vs Galaxy Watch8 40mm
Which one should you buy?
Who leads where?
- CaseGalaxy Watch8 40mm
- Battery and ChargingApple Watch Ultra 3
- PerformanceApple Watch Ultra 3
Wins are counted from the official values in the table below; the BUY / CONSIDER / WAIT call comes from each product's own decision box. We do not predict prices.
The differences in short
Case Size: Apple Watch Ultra 3 49 mm, Galaxy Watch8 40mm 40 mm. Apple Watch Ultra 3 leads on Battery Life: up to 42 hours against up to 40 hours. ECG App is the same on both: Yes. Water Resistance: Apple Watch Ultra 3 100m, Galaxy Watch8 40mm 5 ATM.
Which one for what you do?
Health Tracking
Galaxy Watch8 40mm
77% – 65%
Sport & Outdoors
Apple Watch Ultra 3
90% – 58%
Battery Life
Apple Watch Ultra 3
76% – 50%
Daily Use
Galaxy Watch8 40mm
71% – 53%
The percentages are Kacbu Match scores: computed from official specifications for that use, with no price in them.
 AppleApple Watch Ultra 3No reviews yet |  SamsungGalaxy Watch8 40mmNo reviews yet | |
|---|---|---|
| Key Differences | ||
| Case Size | 49 mm | 40 mm |
| Processor | Apple S10 | No data |
| Battery Life | up to 42 hours | up to 40 hours |
| ECG App | Yes | Yes |
| Water Resistance | 100m | 5 ATM |
| Health Sensors and Features | ||
| Heart Rate Sensor | Yes | Yes |
| SpO2 Sensor | Yes | Yes |
| ECG Sensor | Yes | Yes |
| Skin Temperature Sensor | Yes | Yes |
| ECG App | Yes | Yes |
| Atrial Fibrillation Notification | Yes | Yes |
| Sleep Tracking | Yes | Yes |
| Fall Detection | Yes | Yes |
| Crash Detection | Yes | No data |
| Display | ||
| Size | No data | 1.3" |
| Panel | OLED (LTPO3) | Super AMOLED |
| Resolution | 422x514 | 438x438 |
| Peak Brightness | 3000 nit | 3000 nit |
| Always-On Display | Yes | Yes |
| Case | ||
| Case Size | 49 mm | 40 mm |
| Case Thickness | 12 mm | 8.6 mm |
| Weight | 61.6 g | 30.0 g |
| Case Material | Titanium | Aluminum |
| Positioning and GNSS | ||
| GNSS Receiver | Yes | Yes |
| Dual-Band GNSS | Yes | Yes |
| GNSS Systems | GPS, GLONASS, Galileo, QZSS, BeiDou | GPS, Glonass, Beidou, Galileo |
| Battery and Charging | ||
| The figure the maker states | up to 42 hours | up to 40 hours |
| What that figure measures | Normal use | With always-on display off |
| Capacity | No data | 325 mAh |
| Charging Type | Fast charging | No data |
| Water and Dust Resistance | ||
| Water Resistance | 100m | 5 ATM |
| IP Rating | IP6X | IP68 |
| Rated Depth | 40 m | No data |
| MIL-STD-810 | MIL-STD-810H | MIL-STD-810H |
| Performance | ||
| Processor | Apple S10 | No data |
| RAM | No data | 2 GB |
| Storage | 64 GB | 32 GB |
| Connectivity | ||
| Cellular | Optional | Optional |
| Wi-Fi | Wi-Fi 4 | Wi-Fi 4 |
| Bluetooth | 5.3 | 5.3 |
| NFC | No data | Yes |
| Speaker | Yes | No data |
| Microphone | Yes | No data |
| Software | ||
| Operating System | watchOS | Wear OS |
| Phone Compatibility | iPhone 11 or later (iOS 26+) | No data |
The two products are level on the compared specs.
This table is based on manufacturers official specifications. Winning on paper does not always mean a difference in everyday use.