Apple Watch Series 12 review: A new heart rate sensor and a readiness score make this the best smartwatch on the market

"Your heart tells a story of your health, and it’s a story worth hearing," said Apple, as it announced the updated Apple Watch Series 12, with the most accurate heart rate sensor yet. It's not often a tech keynote makes me emotional, but as a health writer, this one did. Maybe I was jet-lagged, or maybe I believe that these huge health updates might make this the best smartwatch on the market.

I spend my days writing about how the best prediction of longevity is how healthy your heart is. With a new heart rate sensor, the Apple Watch Series 12 gives you a heart rate reading every five seconds, 60 times more frequent than the Apple Watch Series 11. This supports HRV readings, a new readiness score that gives you deeper insights into when to push and when to recover, and longevity features in the updated Health app.

The downsides? Everyone I talk to hates the fact that the watch has a built-in microphone for new audio intelligence features coming later this year, but I’ll get into that below. I’ve been wearing it for the past week, and I’m impressed — read my full Apple Watch Series 12 review to find out more.

Apple Watch Series 12: Quick facts

• Same 24-hour battery life: Despite the addition of continuous heart rate monitoring, the Apple Watch Series 12 has the same 24-hour battery life as the Series 11
• New S11 chip: Faster, more efficient processing with support for Siri AI features
• Redesigned holistic sensors: Apple says this is the most accurate heart rate sensor on a wearable; heart rate and HRV are sampled more frequently than before; HRV insights are now more readily displayed in the Health app
• New health metrics: Series 12 supports a new Readiness score and Health Age metric
• Siri AI features: The watch ships with support for Siri AI voice assistance; new "Audio Intelligence" features help you better remember life's important details

Apple Watch Series 12: Specs

Apple Watch Series 12 review: Price and availability

The Apple Watch Series 12 is available for preorder starting September 9, with units expected to arrive on September 18. The Series 12 has the same starting cost as the Series 11 — $399.

In addition to the standard aluminum and upgraded titanium case options, the Apple Watch Series 12 is also available in two ceramic finishes: Pearl White and Night Blue.

See a full breakdown of pricing for all the case options and sizes below:

• Apple Watch Series 12, 42mm, GPS (Aluminum): $399
• Apple Watch Series 12, 42mm, GPS+5G (Aluminum): $499
• Apple Watch Series 12, 46mm, GPS (Aluminum): $449
• Apple Watch Series 12, 46mm, GPS+5G (Aluminum): $549

• Apple Watch Series 12, 42mm, GPS+5G (Titanium): $699
• Apple Watch Series 12, 42mm, GPS+5G (Titanium): $749

• Apple Watch Series 12, 42mm, GPS+5G (Ceramic): $899
• Apple Watch Series 12, 42mm, GPS+5 (Ceramic): $949

Apple Watch Series 12 review: Design and display

Design-wise, the Apple Watch Series 12 looks pretty identical to the Apple Watch Series 11: it comes in two different sizes, 42mm and 46mm, but with the newer watch, there are more color and casing options to choose from. The Apple Watch 11 came in rose gold, silver, space gray, and jet black in an aluminum case, and gold, natural, or slate in titanium. You get more choices with the Apple Watch 12, which comes in dark bronze, light gold, black, and space gray in the aluminum case, radiant gold and natural in the titanium case, and pearl white or night blue in the ceramic case.

I’ve been wearing the 42 mm dark bronze aluminum Apple Watch, and I love how lightweight and comfortable it is on the wrist. In real life, the light gold Apple Watch looks like jewelry, and the ceramic cases really are beautiful.

The biggest difference, design-wise, is on the back of the watch — the heart rate sensor has been completely redesigned, but more on that below. The Apple Watch Series 12 also has that built-in microphone I mentioned above for all of the audio intelligence features coming later this year.

Apple Watch Series review: Health and fitness tracking

There’s no doubt about it: as a fitness tracker, the Apple Watch Series 12 is more accurate than its predecessor, and that’s down to the new heart rate sensor. When looking at the two monitors side-by-side, the Series 12 and Ultra 4 have a “32-petal design,” whereas the older watches had a two-petal design. This refers to the spoke-like lines coming out of the electrode. The green LED lights, which measure your heart rate by shining light into the skin, are bigger and more powerful.

If you’ve ever worn an Apple Watch to bed and woken up in the night to a harsh green glow underneath your wrist, you’ll love this update. That glaring light is finally gone — and so is the feeling that you’re about to be abducted by a UFO.

But more than that, heart rate data lies at the heart of a lot of health features on the Apple Watch, including HRV, workouts, and ovulation prediction, so a better heart rate sensor means the watch is doing all of these, well, better. Apple also said the new heart rate monitor works better on certain skin tones, though it will still likely struggle to read heavily tattooed wrists. Your heart-rate complication can update every five seconds, 60 times more frequently than it did on the Apple Watch Series 11. Inside the Heart Rate app, there's a rolling two-minute chart. And HRV, including overnight and recovery data, is much easier to surface directly from the watch.

Previously, Apple only allowed continuous heart rate monitoring during a workout, so this is a huge step in the right direction. On the Apple Watch Series 12, you’ll be able to see your Recovery HRV score, which shows signs of stress and recovery, as well as your overall HRV, which offers insights into your overall health. You can now see from your wrist if your heart rate suddenly spiked, and through the new daytime Vitals app, you're getting a much more immediate picture of what's happening, rather than having to wait till you’re asleep.

I’ve been testing the new heart rate sensor alongside a Garmin chest strap, and have found the Apple Watch Series 12 to be pretty much spot on. Here’s a graph from my recent run:

The new sensors also feed into the new daily Readiness score, which is only available on the Apple Watch Series 12 and Apple Watch Ultra 4. Readiness provides a single score out of ten with one of four different recommendations: Recover, Pace Yourself, Ready, or Go For It. Readiness updates throughout the day as new data comes in, and is based on your overnight vitals, sleep score, recent physical activity, and training load.

To get a Readiness score, you need to wear the watch for seven nights and get at least four hours of sleep per night. I have done that, but sadly, my Apple Watch 12 got as confused as my internal body clock was on my flight back from Cupertino, and only registered two hours of sleep for my night of travel. I’ll update this review as soon as I get a score.

There are also new changes coming to the Health app later this year, including a new Health Age score that compares your physical fitness to the average for your age range, and a greater emphasis on things like sleep trends, heart data, and longevity metrics. Again, I’ll be testing them as soon as they drop.

One very minor, but exciting update I’ve found during my testing is the Steps watch face compilation you can now get on the Apple Watch 12. Again, Apple isn’t reinventing the wheel, but you can now see your daily step count from your watch face, without the need for any third-party app. Unfortunately for folks with an older Apple Watch, this is a hardware thing, as Apple says it relies on the more accurate S11 chip, so older watches won’t get the updated pedometer.

Apple Watch Series 12 review: Audio Intelligence

Now to address the elephant in the room — the Audio Intelligence features launching on the Series 12 and Ultra 4. Here’s everything you need to know about the new Audio Intelligence features, but in a nutshell, the two features everyone is talking about are Live Rewind and Siri Recap.

Neither are available for me to test just yet; they are coming later in the year, but essentially, Live Rewind allows you to double-click on the Digital Crown of your Apple Watch and get a 15-second recap of what was just said around you. The Watch will play an audible chime even if your watch is on silent and puts a microphone indicator on screen, so people around you will know you’re recording. The example Apple gave was if you’d missed the specials at a restaurant, or missed a colleague's name, you could read it from your watch. I think there’s a compelling reason here, say, if you have ADHD or struggle with auditory processing.

The trickier sell, for me and most people I’ve spoken to, is Siri Recap. This records ambient audio every 15 minutes to create an itemized summary of your day. Yep, you heard that correctly. Apple put a lot of stress on privacy when demoing this new feature — raw audio isn’t saved, uploaded, or retrievable, and Siri Recap doesn’t identify individual speakers. It’s also designed to exclude sensitive information or hate speech.

However, even with these features, there’s still the slightly blurred line around the fact that my conversation could, in theory, appear on someone else’s Siri Recap without my consent to being recorded. Although this isn’t an Apple problem, it’s a living-in-2026 problem, as the same questions are being leveled at the ambient AI, cameras, and microphones in smart glasses and other wearable devices.

Personally, I can’t think of a situation where I’d need a computer to give me a summary of my day, but I’ll reserve judgment until I’ve been able to go hands-on with the features later in the year. I’d also add that these are all features that you have to opt in to — they are automatically disabled when you unbox the watch.

Apple Watch Series 12 review: Battery life

The Apple Watch Series 12 has the same 24 hours of battery life as the Series 11, but Apple has given us faster charging as well as a bunch of new sensors. You can now get up to 80% charge in about 30 minutes, 15 minutes for up to 12 hours of normal use, and 5 minutes for up to 10 hours of sleep tracking.

If, like me, you’re a runner, you will get slightly longer GPS-mode battery life — 10 hours instead of 8 on the Series 11.

I’ve found Apple’s battery life claims to be pretty accurate, and, as someone who frequently forgets to charge her watch before bed, I have definitely noticed how much faster the Series 12 charges.

Apple Watch Series 12 review: Should you buy?

A week later, I can confidently say that it wasn’t just the jet lag making me emotional in the keynote — as someone who writes about health and fitness for a living, this is the best Apple Watch on the market for most people. In fact, it’s the first year since the Ultra launched in 2022 that I’d be torn about which to shop for.

Between the upgraded heart rate sensor, the new Readiness score — because knowing when to rest is just as important as closing your rings — and an actual dedicated step-counting app, this watch completely outclasses the Series 11. I know other brands have been doing all of the above for years, but none of them are also like having an extension of your iPhone on your wrist, and that’s why when Apple does it, it feels different.

Audio Intelligence is the flashy upgrade and Siri Recap is going to generate headlines, but personally, I think it’s the continuous heart-rate sensing and better recovery information that have changed the day-to-day feel of the Apple Watch on my wrist when testing the Series 12. Buy the Ultra 4 if you want 50 hours of battery life, you’re into diving, or you just want to make a statement, but if you’re looking for a smartwatch that’ll help you make actionable changes to your health, the Apple Watch Series 12 is a good place to start.