Apple's high-end smartwatch just got a new chip, more AI features, better heart rate sensing, and more. Here's how the Apple Watch Ultra 4 compares to its predecessor.
On Wednesday, alongside the iPhone Duo and iPhone 18 Pro, Apple unveiled the Apple Watch Ultra 4. Though the outside of the watch is effectively indistinguishable from the Apple Watch Ultra 3, the hardware inside packs a significant punch.
With Siri Recaps, Live Rewind, sound recognition, a redesigned health sensor system, better battery life, and an updated Health app on iOS 27, there's a lot to cover.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Technical specifications
| Specifications | Apple Watch Ultra 4 | Apple Watch Ultra 3 |
|---|---|---|
| Starting price | $799 | $799 |
| Size | 49mm | 49mm |
| Display | Retina LTPO3 OLED display Up to 3,000 nits | Retina LTPO3 OLED display Up to 3,000 nits |
| Case Materials | Titanium | Titanium |
| Health Sensors | Always-on optical heart sensor Second-generation electrical heart sensor Temperature sensor | Third-generation optical heart sensor Electrical heart sensor Temperature sensor |
| Water Resistance | 100 meters | 100 meters |
| Battery Life | Up to 50 hours (84 in Low Power Mode) | Up to 42 hours (72 in Low Power Mode) |
| Recharging | Wireless | Wireless |
| Connectivity and Sensors | Emergency SOS Emergency SOS Via Satellite Messages via Satellite Find My via Satellite Fall Detection Crash Detection Always-on altimeter Accelerometer Gyroscope Compass Depth Gauge Water temperature sensor | Emergency SOS Emergency SOS via Satellite Messages via Satellite Find My via Satellite Fall Detection Crash Detection Always-on altimeter Accelerometer Gyroscope Compass Depth Gauge Water temperature sensor |
| Satellite Navigation | GPS Galileo QZSS BeiDou | GPS Galileo GLONASS QZSS BeiDou |
| Color Options | Natural Titanium Black Titanium | Natural Titanium Black Titanium |
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Case size, design, dimensions
For the Apple Watch Ultra 4, Apple opted to use a tried-and-true design. As a result, the new model is effectively identical to the preceding Apple Watch Ultra 3.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Apple hasn't made any changes to the design of its top-of-the-line smartwatch. Image Credit: Apple.
The Apple Watch Ultra 4 is a bulky smartwatch, with a flat display and curved edges. It has an Action button and Digital Crown on the side of the titanium enclosure. The latest Apple Watch Ultra has kept the 49mm case size of preceding models.
Still, the Apple Watch Ultra 4 is slightly heavier. In Natural Titanium, it weighs 63 grams, while the Black Titanium version has a weight of 63.1 grams.
The Apple Watch Ultra 3 in Natural Titanium weighed 61.6 grams, while the Black Titanium version weighed 61.8 grams. The new model is less than two grams heavier.
The Apple Watch Ultra 4 still uses sapphire crystal and ceramic for the front and back, respectively. Meanwhile, the main enclosure is made from 100% recycled titanium on both the Apple Watch Ultra 4 and Apple Watch Ultra 3.
There's no change in terms of dimensions, either. The Apple Watch Ultra 4 measures 49mm by 44mm, with a thickness of 12mm, matching that of the Apple Watch Ultra 3.
Durability remains unchanged as well with the Apple Watch Ultra 4. The new model is certified for MIL-STD 810H durability, IP6X dust resistance, and water resistance of up to 100 meters (328 feet).
As for the display, both the Apple Watch Ultra 4 and Apple Watch Ultra 3 have an Always-On LTPO3 wide-angle OLED screen. It has a maximum brightness of 3,000 nits.
For both Apple Watch models, the display area is 1,245 square millimeters, with a resolution of 422 by 514 pixels.
While the titanium casing and OLED display haven't changed with the Apple Watch Ultra 4, the hardware inside certainly has.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Processing hardware, performance
The Apple Watch Ultra 4 boasts the new S11 chip. It has a power-efficient, always-on processor with a new Secure Exclave. Inside, an audio buffer securely manages raw audio for processing.
Apple Watch Ultra 4 vs Apple Watch Ultra 3: The S11 chip offers better performance and enables new Apple Intelligence features. Image Credit: Apple
Apple's S11 chip also has a faster CPU, GPU, and Neural Engine, all derived from the A20 Pro chip. The S11 CPU has two efficiency cores and a Neural Accelerator. Its last-level cache is 50% larger than the one in the S10 chip.
Its quad-core Neural Engine similarly offers increased bandwidth compared to the preceding generation. Additionally, the S11's single-core GPU offers increased bandwidth and compute, says Apple. The company calls the S11 its most powerful wearable chip yet.
All that extra power isn't just for show, either, as the Apple Watch Ultra 4 supports all-new Apple Intelligence and Health features.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Health features
Health-focused functionality has always been a staple of the Apple Watch Ultra, and the fourth-generation model is no exception. Relative to its predecessor, the Apple Watch Ultra 4 features a redesigned health sensing system.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Apple has added multiple health-related features, including a new Readiness score.
Apple says the new hardware is built on its innovative health sensing foundation, and that it improves three core elements.
The larger electrode surface area enables better skin contact during electrocardiogram (ECG) readings. Additionally, redesigned photodiodes were arranged into a ring to capture light more efficiently.
Larger green LEDs, with improved power efficiency, are used to support accurate heart rate measurements during the day. Combined, these changes allow for improved optical sensing.
Relative to Apple Watch Ultra 3, the new health sensing system in the Apple Watch Ultra 4 delivers higher-frequency, continuous heart rate data. This metric serves as a key indicator of overall health, says Apple.
The Apple Watch Ultra 4 takes background heart rate readings every five seconds. That's 60 times the frequency of readings on the Apple Watch Ultra 3.
Apple's upgraded health sensing system also samples heart rate variability (HRV) twenty-four times more frequently than the previous model. This means the Apple Watch Ultra 4 samples HRV every five minutes.
HRV indicates how well someone's body responds to stress. Higher values are typically associated with better overall recovery, says Apple.
HRV is included in the Overnight view and a new Daytime view, both of which are in the Vitals app on the Apple Watch Ultra 4.
Apple conducted a study comparing the Apple Watch Ultra 4's health sensing system to other wearable products. The company used an ECG chest strap as a reference.
Over a thousand participants engaged in a variety of activities for the study, including cycling, HIIT workouts, running, and more.
The study found that the Apple Watch Ultra 4 has "the most accurate heart rate sensing in a wearable." Improved sensors aren't the only new experience with the Apple Watch Ultra 4.
The Readiness experience uses the wearer's recent activity, vitals, and sleep data to offer an idea of their body's overall capacity during the day. A numerical score and description guide the wearer on the amount of physical activity they should do.
The Readiness score can be viewed via the Health app on iOS, and it updates during the day. The Health app on iPhone has been redesigned as well.
Apple Intelligence uses Apple Watch data to offer custom suggestions via the new Insights tab. Dynamic, user-tailored recommendations appear in other areas of the app.
There's also a Health Age feature, which explains how the wearer's health metrics, like VO2 Max and sleep data, compare to their actual age. Apple's new Longevity tab uses iPhone and Apple Watch data to assess the user's overall health.
Additionally, the iPhone and Apple Watch can be used together to conduct specific tests, like VO2 Max assessments.
During the test, the iPhone camera records your movements as it displays a video of what to do. Simultaneously, the Apple Watch Ultra 4 records health-related metrics.
The upgraded sensors in the Apple Watch Ultra 4, coupled with more frequent heart rate measurements, make the watch the go-to option.
In terms of Health features, Apple Watch Ultra 3 is no slouch, either. It offers blood oxygen monitoring and hypertension notifications, but the Apple Watch Ultra 4 simply has more to offer.
The same is true when Apple Intelligence features for the Apple Watch are taken into account.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Apple Intelligence
Though the Apple Watch Ultra 3 already offers a limited number of Apple Intelligence capabilities, such as the Workout Buddy feature, the Apple Watch Ultra 4 takes things to the next level with Audio Intelligence.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Audio Intelligence delivers three new features for the Apple Watch. Image Credit: Apple.
Audio Intelligence encompasses multiple sound-related capabilities available on the Apple Watch Ultra 4.
As a new accessibility feature, Apple's new top-of-the-line smartwatch includes sound recognition. This lets the watch detect sounds like sirens, doorbells, crying babies, and more. The end user receives an on-screen notification for each detected sound.
Live Rewind lets you replay sentences detected by the Apple Watch Ultra 4 in the form of a text snippet. It only goes back fifteen seconds, but it's enough to let you catch a book recommendation or list that you might have missed. No audio recordings are created or stored.
Siri Recap can summarize conversations had while wearing the Apple Watch Ultra 4. The feature is entirely optional, though. Apple's commitment to user privacy is still a priority with Audio Intelligence.
The company emphasizes that audio files are not stored anywhere, and that the audio data is not accessible, even to Apple. It's only used to provide summaries of conversations when you allow it to.
Live Rewind and Siri Recap both require Siri AI, meaning you'll need an iPhone 16 or newer to take advantage of these two features. Audio Intelligence will be available later in 2026, with Siri Recap and Live Rewind arriving in beta later in 2026.
In terms of Apple Intelligence features, it looks as though the Apple Watch Ultra 4 can run circles around its predecessor. Battery life has been greatly improved as well.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Battery life, connectivity
Apple says the Apple Watch Ultra 4 is equipped with a larger battery. Coupled with the S11 chip and new health sensing system, it lets the Apple Watch Ultra 4 achieve a remarkable 50 hours of battery life. That's up from 42 hours on the Apple Watch Ultra 3.
Apple Watch Ultra 4 vs. Apple Watch Ultra 3: Apple claims the Apple Watch Ultra 4 can last up to 45 hours in the new Max Extended workout mode. Image Credit: Apple.
As for workout tracking with full GPS and heart rate monitoring, the Apple Watch Ultra 4 is capable of delivering up to 18 hours of battery life.
Extended Workout activates Low Power Mode and turns off the always-on display. During the workout, running form metrics are unavailable in this mode.
In exchange for this limited functionality, the new Extended Workout mode delivers up to 25 hours of battery life.
There's also a new Max Extended workout mode, which offers up to 45 hours of battery life.
Apple says Max Extended Workout turns on Low Power Mode during workouts and disables alerts, splits, and select metrics. This mode also turns off the always-on display.
The Extended Workout and Max Extended Workout modes are not available on the Apple Watch Ultra 3.
In Low Power Mode, the Apple Watch Ultra 4 can last up to 84 hours, up from 72 hours on the preceding model. Apple says the Apple Watch Ultra 4 can gain up to 18 hours of use from a 15-minute charge, again up from 12 hours on the Apple Watch Ultra 3.
In terms of connectivity, the Apple Watch Ultra 4 includes support for Wi-Fi 4 as well as Bluetooth 5.3. While Bluetooth and Wi-Fi support remain unchanged from the Apple Watch Ultra 3, Apple did make a minor satellite-navigation change.
The Apple Watch Ultra 4 supports GPS, Galileo, QZSS, and BeiDou. However, Apple has dropped support for GLONASS, which was available on the Apple Watch Ultra 3.
With GPS, Galileo, QZSS, and BeiDou, the Apple Watch Ultra 4 and Apple Watch Ultra 3 receive position information using the L1 and L5 bands. These satellite-navigation systems use CDMA (Code Division Multiple-Access) to transmit signals.
GLONASS, meanwhile, utilizes a different transmission architecture, called FDMA (Frequency-Division Multiple Access). On the Apple Watch Ultra 3, it delivers position information over only the L1 band. Support for GLONASS is not available with the Apple Watch Ultra 4.
Though Apple did not explain why it removed GLONASS support, its absence may actually have improved GPS accuracy and battery life. The hardware no longer uses energy for single-frequency GLONASS signals.
Apple claims the Apple Watch Ultra 4 has "the most accurate on-device GPS in a sports watch." This is according to an August 2026 study that compared the Apple Watch Ultra 4 to "industry-leading dual-frequency GPS sports watches" available at the time.
Overall, the absence of GLONASS support likely won't mean much to potential Apple Watch Ultra 4 buyers. The seemingly improved GPS accuracy, however, might appeal to those considering the new model.
Connectivity details aside, the Apple Watch Ultra 4 offers 8 hours of extra battery life. With all the new health-related enhancements and performance, it's the obvious choice if you're looking to upgrade. Pricing hasn't changed, either.
Apple Watch Ultra 4 vs Apple Watch Ultra 3: Pricing
Apple offered the Apple Watch Ultra 3 for $799. It was sold in Natural and Black Titanium color options.
The same is true for the Apple Watch Ultra 4, which is also priced at $799 in both Natural and Black Titanium variants.
Where to buy the Apple Watch Ultra 4 and Apple Watch Ultra 3
The Apple Watch Ultra 4 can be preordered today at Apple.com, with prices starting at $799. It hits stores on September 18.
Limited Apple Watch Ultra 3 inventory remains at third-party Apple resellers, with Amazon knocking up to $20 off the last-gen models. You can browse the latest offers in our Apple Watch Ultra 3 Price Guide.