The Apple Watch Series 12 is now available for pre-order, and unlike last year's model, it brings a substantial list of changes over its predecessor. Here's everything that's new. Last year, the Series 11 introduced just four changes over the Series 10, making it perhaps the smallest generational upgrade in the device's history. The Series 12 is a far more meaningful refresh, even though it essentially retains the same design for a third consecutive year. It launches on Friday, September 18, at the same $399 starting price as the Series 11, which Apple has now discontinued. This guide lists all of the differences between the Series 11 and Series 12 models to help you understand the changes: Apple Watch Series 11 Apple Watch Series 12 S10 chip (2024) S11 chip (2026) 2GB RAM 4GB RAM Electrical heart sensor "Health Sensing System" with second-generation electrical heart sensor Third-generation optical heart sensor Fourth-generation, always-on optical heart sensor Heart rate tracking High-frequency background heart rate tracking (every five seconds) HRV Recovery HRV and overall HRV (measured up to 24x more often) Vitals app with heart rate, respiratory rate, wrist temperature, and sleep duration Vitals app with heart rate, respiratory rate, wrist temperature, sleep duration, and HRV, plus daytime vitals view Readiness app More accurate step tracking Steps complication Audio Intelligence (Live Rewind, Siri Recap, Sound Recognition, and Shazam) Ion-X glass with 2x scratch resistance (aluminum models) Ceramic Shield 2, 60% tougher than Ion-X (aluminum models) Metal and sapphire crystal back Aluminum or titanium and zirconia back Aluminum or titanium case Aluminum, titanium, or ceramic case Aluminum: Jet Black, Rose Gold, Silver, and Space Gray Aluminum: Dark Bronze, Light Gold, Black, and Space Gray Titanium: Slate, Gold, and Natural Titanium: Radiant Gold and Natural Ceramic: Pearl White and Night Blue Hermès: Silver titanium Hermès: Silver and Radiant Gold titanium 15 minutes of charging for up to 8 hours of normal use 15 minutes of charging for up to 12 hours of normal use 5 minutes of charging for up to 8 hours of sleep tracking 5 minutes of charging for up to 10 hours of sleep tracking Now discontinued From $399 The new ceramic case marks the first ceramic Apple Watch since the Series 5 Edition in 2019, but it is slightly larger than the other models and weighs up to 52.9 grams in its 46mm Night Blue configuration. Even the aluminum and titanium models are now 1mm wider and around 2 grams heavier than their predecessors. At the same time, the display appears to have shrunk slightly, even though its resolution is unchanged. Apple lists the 46mm Series 12 with 1,196 sq mm of display area, 2% less than the 1,220 sq mm of the Series 11, while the 42mm model drops 1.9% from 989 sq mm to 970 sq mm. A marginally smaller screen in a wider case means thicker borders, and Apple also appears to have pulled the case back slightly around a larger front glass, which could make them look even more prominent. The Series 10 went through a similar change in 2024, when its visible aluminum edge shrank compared to the Series 9 but its overall bezel, including the black border under the glass, actually grew. The shift is less dramatic this time around, since the Series 12 keeps the same basic case design. Here's how the two generations compare in size, weight, and display area: 46mm Apple Watch Series 11 Apple Watch Series 12 Dimensions 46mm x 39mm x 9.7mm 46mm x 40mm x 9.7mm Display area 1,220 sq mm 1,196 sq mm Aluminum (GPS) 37.8 grams 39.5 grams Aluminum (Cellular) 36.9 grams 38.6 grams Titanium 43.1 grams 44.9 grams 42mm Apple Watch Series 11 Apple Watch Series 12 Dimensions 42mm x 36mm x 9.7mm 42mm x 37mm x 9.7mm Display area 989 sq mm 970 sq mm Aluminum (GPS) 30.3 grams 32.2 grams Aluminum (Cellular) 29.7 grams 31.5 grams Titanium 34.6 grams 36.5 grams The new ceramic models, which have no Series 11 equivalent, are larger and considerably heavier still: Ceramic 46mm 42mm Dimensions 47mm x 41mm x 9.85mm 43mm x 37mm x 9.85mm Pearl White 51.3 grams 41.7 grams Night Blue 52.9 grams 42.8 grams The most significant upgrade between the two devices is the new Health Sensing System. It uses a larger electrode surface for better skin contact during ECG readings, redesigned photodiodes laid out in a ring for more efficient light capture, and bigger, more power-efficient green LEDs. The result is that the Series 12 measures heart rate every five seconds throughout the day, 60 times more frequently than before, and samples HRV up to 24 times more often. Apple claims this gives the Series 12 the most accurate heart rate sensing of any wearable. That higher-frequency data powers several new health features that are exclusive to the Series 12. The Readiness app weighs up your recent activity, training load, vitals, and sleep score to produce a single daily score out of 10, alongside a recommendation ranging from "Recover" to "Go For It." There is also a separate Recovery HRV metric, a daytime view in the Vitals app, and new watch face complications for real-time heart rate and step count. Apple has also rebuilt its pedometer model and says the Series 12 now offers the most accurate step tracking of any smartwatch. The Series 12 is the first model in two years to get a new chip, with the S11 replacing the S10 that powered both the Series 10 and Series 11, which itself was almost identical to the S9 chip from 2023. The new model also has twice as much RAM, with 4GB compared to 2GB in the Series 11. The S11 chip enables Audio Intelligence, a new set of features exclusive to the Series 12 and Ultra 4. Live Rewind displays a transcript of the last 15 seconds of conversation with a double press of the Digital Crown, Siri Recap generates summaries of conversations, Sound Recognition alerts deaf or hard of hearing users to sounds like sirens and doorbells, and Shazam can automatically identify music playing nearby. According to Apple, audio is processed in a hardware-isolated Secure Exclave on the S11 chip and is never recorded. Everyday battery life is unchanged at up to 24 hours, or up to 38 hours in Low Power Mode. The improvements instead focus on workouts and charging. The Series 12 offers up to 10 hours of battery life during an outdoor workout, which Apple says is 25% more than the Series 11, and 15 minutes of charging now delivers up to 12 hours of use rather than eight. All other aspects, such as display resolution and brightness, 64GB of storage, 5G connectivity, and water and dust resistance all carry over from the Series 11 unchanged. Is It Worth Upgrading? For new buyers, the Series 12 is the obvious choice. It costs the same $399 that the Series 11 did at launch, while adding a more capable health sensing system, double the RAM, and a considerable list of exclusive features. With a new chip and more memory, it is also likely to be better placed for future Apple Intelligence features. The Series 11 is the better value option only when it can be found heavily discounted, which is likely as third-party retailers clear their remaining stock. Last year, we concluded that virtually no users should upgrade from a Series 10 to a Series 11. This year, the picture is more nuanced. For most Series 11 owners, there is still no general-purpose reason to upgrade, since many key features are unchanged and Siri AI is coming to the Series 11 anyway. However, the Series 12 is worth considering if you rely on your Apple Watch for training and recovery insights, since continuous heart rate tracking, Recovery HRV, and Readiness are all exclusive to the new model. Deaf and hard of hearing users may find Sound Recognition a compelling reason to upgrade on its own, and some users will simply want the new ceramic finish. Series 11 owners who are happy to wait may prefer to hold out for next year's "Series 13," which is rumored to bring the first major redesign since the Series 10, including a new band attachment system. By contrast, upgrading is much easier to justify if you have a Series 9 or older. Series 10 owners would gain a new, thinner design with a wider screen, a tougher display on aluminum models, and a longer battery life in addition to all of this year's changes.Related Roundup: Apple Watch 12Buyer's Guide: Apple Watch (Buy Now)Related Forum: Apple WatchThis article, "Apple Watch Series 11 vs. Series 12 Buyer's Guide: 25+ Upgrades Compared" first appeared on MacRumors.comDiscuss this article in our forums
