Apple Watch Ultra 4 is official: All the upgrades explained

(Image credit: Apple) Apple just announced the Apple Watch Ultra 4 alongside the Apple Watch Series 12, iPhone Duo, and iPhone 18 Pro at the September 9th "Surprise and Shine" event in Cupertino, California.Boasting loads of new wellness tools, improved heart rate tracking, better battery life, an upgraded processor, and a handful of cool AI features, here's everything you need to know about the Apple Watch Ultra 4.Apple Watch Ultra 4: Upgrades cheat sheetPrice and release: The Apple Watch Ultra 4 is available for preorder starting today and will be available on September 18; the price is $799, the same as the Ultra 3Design: The Apple Watch Ultra 4 looks similar to its predecessor; available in Black or Natural TitaniumHealth features: Updated health sensing system; improved heart rate and heart rate variability (HRV) tracking; HRV reflected in Vitals app; new Readiness metric; new Health Age score; redesigned Health app with improved recovery insights and personalized AI health/fitness guidance that updates dynamically; Health app now supports personal health data and lab resultsAI features: Support for Siri AI voice assistant; Live Rewind lets you ‘go back in time’ up to 15 seconds; Sound Recognition can auto-alert users to common sounds like sirens and alarms; Siri Recap takes high-level notes of conversations and generates summariesUnder-the-hood: Upgraded S11 processorBattery life: Improved battery performance lasts up to 48 hours per charge; up to 18 hours when recording a workout with heart rate and GPS trackingThe Apple Watch Ultra 4 is a substantial upgrade over the Apple Watch Ultra 3, which is currently one of the best smartwatches you can buy.Apple Watch Ultra 4: Price and availability The Apple Watch Ultra 4 costs $799, the same as all the Apple Watch Ultra models that came before it. Available for preorder on launch day (September 9), the Apple Watch Ultra 4 will be available globally starting on September 18 in your choice of Black or Natural Titanium.Apple Watch Ultra 4: Health upgradesImproved heart rate tracking: The Apple Watch Ultra 4 and Series 12 boast “the most accurate heart rate tracking in wearables.” That is, of course, according to Apple’s own internal testing. To be fair, Apple completely overhauled the sensor array on the underside of the watch, making a number of significant improvements to its functionality.Both the optical and electrical components have been reworked for more precise, efficient performance. More powerful LEDs measure your heart rate every five seconds, a 60-fold increase in sampling frequency over prior models.Heart Rate Variability (HRV) is now measured every 15 seconds, a 24-fold increase compared to before. Speaking of HRV, users can now view that dynamic metric from the Heart Rate app. HRV is also logged in your overnight vitals report.Get instant access to breaking news, the hottest reviews, great deals and helpful tips.Dynamic Readiness scoreImproved step count trackingRedesigned Health app focused on trendsApple Watch Ultra 4: New AI featuresLive Rewind and Sound Recognition Siri AI with Siri RecapApple Watch Ultra 4: Battery lifeBattery life on the Apple Watch Ultra 4 has been increased to 48 hours per charge, up from 42 hours per charge for the Ultra 3. When using the Ultra 4 to log an outdoor workout with continuous GPS and heart rate tracking, users can expect about 18 hours of use.Extended workout tracking mode bumps that number to 25 hours per charge, while a new Max Extended mode increases battery life to an impressive 45 hours per charge.The Ultra 4 charges a little faster than its predecessor. Apple says a 15-minute charge should provide up to 18 hours of use.This is a developing story. Check back soon for more details. Follow Tom's Guide on Google News and add us as a preferred source to get our up-to-date news, analysis, and reviews in your feeds. Alternatively, you can read our content on the Tom's Guide app available now for iOS and Android. More from Tom's GuideWe asked 368 people what they want from the Apple Watch Ultra 4. Here’s the resounding answer (and it’s not AI)I’ve been writing about the Apple Watch for the past decade: Here’s the rumored update I’m most excited about for the Apple Watch Ultra 4Leaked Apple Watch 12 design change is the opposite of an upgrade — and that has me worried Dan Bracaglia is the Tom’s Guide editorial lead for all things smartwatches, fitness trackers and outdoor gear. With 15 years of experience as a consumer technology journalist testing everything from Oura Rings to instant cameras, Dan is deeply passionate about helping readers save money and make informed purchasing decisions. In the past year alone, Dan has assessed major product releases from the likes of Apple, Garmin, Google, Samsung, Polar and many others. An avid outdoor adventurer, Dan is based in the U.S. Pacific Northwest where he takes advantage of the beautiful surroundings every chance he gets. A lover of kayaking, hiking, swimming, biking, snowboarding and exploring, he also makes every effort to combine his day job with his passions. When not assessing the sleep tracking and heart rate accuracy of the latest tach gadgets, you can find him photographing Seattle’s vibrant underground music community.