Apple Watch Ultra 4 vs. Ultra 3: What the upgrade adds

Both watches start at $799, although the Ultra 3 is no longer sold new through Apple and may be found for less at other retailers. The cases come in natural or black titanium, are water-resistant to 100 meters and look nearly identical. The Ultra 4 weighs up to 1.4 grams more, depending on the case color, and uses a ceramic-and-zirconia back instead of ceramic and sapphire crystal. Both have the same always-on OLED display, with brightness up to 3,000 nits.

The Ultra 4 runs on Apple’s S11 chip, replacing the Ultra 3’s S10, while both models have Wi-Fi 4, Bluetooth 5.3 and 64GB of storage. Apple rates the newer watch for up to 50 hours of normal use or 84 hours in Low Power Mode, compared with 42 and 72 hours, respectively, for the Ultra 3. Short charging sessions also yield more use: 15 minutes provides up to 18 hours of normal use on the Ultra 4, versus 12 hours on the Ultra 3. New Extended Workout and Max Extended Workout modes are rated for up to 25 and 45 hours with continuous GPS and heart-rate readings.

New optical and electrical heart sensors let the Ultra 4 take more frequent readings and measure heart-rate variability up to 24 times more often, Apple said. The watch also adds a Readiness score, a step-counting model and Audio Intelligence features, including Sound Recognition alerts, Live Rewind transcriptions, Siri Recap summaries and automatic music recognition through Shazam. Apple says the tools do not create or store audio recordings; users can turn them off.

Mashable senior editor Stan Schroeder called the Ultra 4 “an essential upgrade” for athletes, particularly those seeking longer battery life and improved heart-rate measurements. Other buyers may prefer a discounted Ultra 3, which has fallen as low as $649 and regularly reaches $699. If both are available at their usual $799 price, the source’s comparison favors the Ultra 4.