Apple Watch Ultra 4 vs Watch Ultra 3 specs comparison

Apple Watch Ultra 4 is the stronger sports watch, mainly thanks to its new Health Sensing System, readiness score and improved battery life of up to 50 hours versus 42 hours on Ultra 3. Ultra 3 is still extremely capable, so upgrading makes most sense for people who value the improved health sensing and extra endurance rather than those expecting a major redesign.

At a glance

What's different?

The strongest database-backed differences, without pretending every different number is an advantage.

Apple Watch Ultra 4

  • Readiness Not available on the other model
  • Processor Apple S11, 64-bit dual-core processor; 4-core Neural Engine; Audio Intelligence
  • 19% longer battery life 50 hours vs 42 hours
  • Voice assistant Siri AI powered by Apple Intelligence

Apple Watch Ultra 3

  • Processor Apple S10, 64-bit dual-core; 4-core Neural Engine
  • Voice assistant Siri
Both include ECG, blood oxygen tracking, skin temperature tracking, HRV tracking, on-board music, Bluetooth calling, a microphone.
Full comparison

The full record

78 specifications across 6 areas, with 9 genuine differences.

1. Design & display 2 differences · no clear overall edge No clear edge
Fact
Apple Watch Ultra 4
Apple Watch Ultra 3
Release date
2026-09-18
2025-09-19
Physical size
49 x 44 x 12 mm
49 x 44 x 12 mm
Weight
63.0 g (Natural), 63.1 g (Black)
61.6 g (Natural), 61.8 g (Black)
Material
Grade 5 titanium case
Grade 5 titanium case
Water resistance
10 ATM; IP6X; MIL-STD 810H; recreational scuba diving to 40 m
10 ATM; IP6X; MIL-STD 810H; recreational scuba diving to 40 m
Color options
Natural Titanium, Black Titanium
Natural Titanium, Black Titanium
Display type
Always-On Retina LTPO3 wide-angle OLED
Always-On Retina LTPO3 wide-angle OLED
Display size
49 mm case
49 mm case
Display resolution
422 x 514 pixels
422 x 514 pixels
Display brightness
Up to 3,000 nits
Up to 3,000 nits
Display protection
Flat sapphire crystal display
Flat sapphire crystal display
2. Battery & charging 1 difference · Apple Watch Ultra 4 leads on Battery life Apple Watch Ultra 4
Fact
Apple Watch Ultra 4
Apple Watch Ultra 3
Battery
Rechargeable lithium-ion battery
Rechargeable lithium-ion battery
Battery life
Up to 50 hours normal use; up to 84 hours in Low Power Mode; up to 18 hours outdoor workout; up to 25 hours Extended Workout; up to 45 hours Max Extended Workout
Up to 42 hours; up to 72 hours in Low Power Mode
Charging
USB-C magnetic fast charging; up to 80% in about 45 minutes
USB-C magnetic fast charging; up to 80% in about 45 minutes
3. Sensors & positioning 1 difference · no clear overall edge No clear edge
Fact
Apple Watch Ultra 4
Apple Watch Ultra 3
GNSS type
Built-in dual-band GNSS
Built-in dual-band GNSS
GPS
Yes
Yes
GALILEO
Yes
Yes
GLONASS
No
Yes
QZSS
Yes
Yes
Beidou
Yes
Yes
Accelerometer
Yes
Yes
Gyroscope
Yes
Yes
Barometric altimeter
Yes
Yes
Compass
Yes
Yes
Ambient light sensor
Yes
Yes
Optical heart rate
Yes (always-on optical heart sensor; high-frequency background tracking)
Yes
Electrical heart rate
Yes
Yes
SpO2
Yes
Yes
Temperature
Yes
Yes
Galvanic skin response
No
No
Microphone
Yes
Yes
Speakers
Yes
Yes
Vibration motor
Yes
Yes
4. Health & activity 1 difference · no clear overall edge No clear edge
Fact
Apple Watch Ultra 4
Apple Watch Ultra 3
Steps
Yes
Yes
Distance
Yes
Yes
Calories burned
Yes
Yes
Floors
Yes
Yes
Sports tracking
Yes
Yes
Sleep
Yes
Yes
Heart rate
Yes
Yes
HRV
Yes (Up to 24x more frequent than Ultra 3)
Yes
Stress
No
No
Blood oxygen
Yes
Yes
Respiration rate
Yes
Yes
Skin temperature
Yes
Yes
ECG
Yes
Yes
Blood pressure
Hypertension notifications (no direct blood-pressure measurement)
Hypertension notifications (no direct blood-pressure measurement)
Body composition
No
No
Glucose
No
No
Hydration level
No
No
UV exposure
No
No
Calorie intake
No
No
Hyperglycemia risk assessment
No
No
Arterial stiffness detection
No
No
Pulse wave arrhythmia analysis
Yes
Yes
Readiness
Yes
No
5. Smart features 4 differences · no clear overall edge No clear edge
Fact
Apple Watch Ultra 4
Apple Watch Ultra 3
Smartphone compatibility
iPhone 11 or later or iPhone SE (2nd generation or later) with iOS 27 or later
iPhone 11 or later with iOS 26 or later
Operating system at launch
watchOS 27
watchOS 26
Processor
Apple S11, 64-bit dual-core processor; 4-core Neural Engine; Audio Intelligence
Apple S10, 64-bit dual-core; 4-core Neural Engine
Storage
64 GB
64 GB
Bluetooth
Yes (5.3)
Yes (5.3)
Wi-Fi
Yes (Wi-Fi 4 / 802.11n, 2.4/5 GHz)
Yes (Wi-Fi 4 / 802.11n, 2.4/5 GHz)
NFC / connected pay
Yes (Apple Pay)
Yes (Apple Pay)
UWB
Yes (2nd-generation UWB)
Yes (2nd-generation UWB)
Cellular
Yes (5G RedCap and LTE on supported regional models)
Yes (5G RedCap and LTE on supported regional models)
Smartphone notifications
Yes
Yes
Bluetooth calling
Yes (standalone on cellular models; via paired iPhone otherwise)
Yes (standalone on cellular models; via paired iPhone otherwise)
Smartphone music control
Yes
Yes
On-board music storage
Yes
Yes
Voice assistant
Siri AI powered by Apple Intelligence
Siri
6. Navigation & safety No significant differences Even
Fact
Apple Watch Ultra 4
Apple Watch Ultra 3
Maps
Yes
Yes
Offline maps
Yes
Yes
Navigation
Yes
Yes
Emergency SOS
Yes
Yes
Satellite SOS
Yes
Yes
Fall detection
Yes
Yes
LED flashlight
No
No
Diving
Yes
Yes
No significant differences in this area.

Individual specifications

These technical specs are correct to the best of our knowledge at the time of publishing.