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Which New Apple Watch Is Right for You? Here’s Everything to Know About the Ultra 4 vs. Series 12
I tested both of the newest Apple Watches—here’s how they compare.
About four years ago, I started getting more serious about running, so I went out and bought my first wearable. I wanted a tracker that seamlessly transitioned between my Apple products, looked at basic metrics like mileage and heart rate, and was on the cheaper side. The answer was the Apple Watch SE.
Fast forward through hundreds of lifting workouts, marathon training runs, and Pilates classes, and I’ve since been grateful to try several more iterations of the Apple Watch. Most recently, I got to test out the Ultra 4 and Series 12, the newest versions that dropped this fall. They promise more accurate heart rate tracking, longer battery lives, and new health metrics.
Still, these watches come with plenty of different features—at different price points—and if you’re interested in buying one or upgrading, you may not want to shell out a ton of cash for stats you’ll never look at. The Series 12 has great baseline health and fitness features while the Ultra 4 comes with off-grid navigation features, full dive capabilities, and offline maps.
But there’s a case to be made for using each of these watches. Ahead, find my honest review of both of them, the new features, and who I think would benefit the most from buying the Ultra 4 versus the Series 12.
New Features on the Apple Watch Ultra 4 and Series 12
Health Metrics
The Ultra 4 and Series 12 feature a higher-tech optical heart sensor, which measures the heart rate every five seconds. Plus, heart rate variability (HRV, or the amount of time between heartbeats that determines your stress level) is measured up to 24 times more often than previous Apple Watch versions. So, the data it provides about your fitness or physiological state is more accurate—which is great considering these new watches track more health metrics than before using the new software on iOS 27 (available on the Series 9 or later versions, SE 3, and Ultra 2 or later).
The Apple Watch Ultra 4 (and Series 12) have introduced a new “readiness” score that tells you how equipped your body is to take on the day. (Several other wearable brands like Oura and Whoop already have their own iterations of this score.) It takes your recent activity, training load, sleep score, and overnight vitals (heart rate, respiratory rate, wrist temperature, and recovery HRV) into account. Then, from a scale of 0 to 10, it gives you a recommendation: Recover, Pace Yourself, Ready, or Go For It. (So far, my health metrics and sleep scores have been suspiciously good!)
There’s also a new “health age” score that uses metrics like your VO2 max, resting heart rate, sleep, and HRV to compare your body to your chronological (real) age. (I didn’t get to test this feature yet, though, because it’s only available on the updated Health app dropping later this year.)
My only complaint is that it’s kind of hard to find the readiness score on the Watch and in the Health app. On the watch, it’s not in the same section that your sleep score is in, and you have to scroll a bit to look at all of the metrics. With the Health app, you need to scroll through every single piece of data, so it’s a little hard to see what to prioritize. (Although you can pin your favorite metrics to look at and kind of block out the rest, which I do like, since some metrics stress me out more than others.) Plus, the readiness score is only found in the Fitness app instead of the Health app, so I wish it was a bit more streamlined, like on other wearables. Hopefully, the updated Health app will solve this issue.
Audio Intelligence
There’s also a wealth of new audio intelligence features, such as sound recognition. For users who are deaf or hard of hearing, the feature listens for sounds like sirens, alarms, or doorbells, and notifies you when it hears them.
Perhaps the more polarizing feature is Live Rewind, which listens to what you’re saying and shows you the last 15 seconds of a conversation in a text bubble just by double-clicking the crown button. In fact, the new Siri Recap can recall your conversation and summarize key points in the new Siri app. That said, Apple is really big on privacy, and says it doesn’t identify or attribute speakers in these conversations.
Ultra 4 vs. Series 12: Design
Before I started using the Series 12, I was using the Series 11, which was also 42 millimeters. I found the screen pretty small when peeking at my metrics during a workout, but it got the job done, and always felt natural and comfortable to sleep in. Plus, it’s sleek and I love the stunning new dark bronze aluminum finish that looks like a gold medal. (Although it also comes in two new ceramic finishes, pearl white and night blue.)
Now that I’ve tried the Ultra 4, though, my favorite thing about it is its size. At 49mm, it’s definitely bulky and looks intense (especially since I have small wrists). But I love how big the screen is—it’s much easier to read texts, look at my stats while I’m running or lifting, and even set timers while I work. Additionally, there’s an extra button for pausing and resuming workouts that isn’t on the Series 12. So, when I’m on a run, I don’t have to swipe to another interface to stop it—I can just tap that button.
The only downside to the bigger size of the Ultra 4 is that when I sleep, it feels quite bulky on my wrist. Once I’m asleep, it obviously doesn’t bother me, but it does take a little bit to get used to.
Ultra 4 vs. Series 12: Battery Life
The Series 12 offers up to 24 hours of everyday battery life and faster charging, as 15 minutes gives you up to 12 hours of additional battery life. (That’s 50 percent more than the Series 11!) I’ve found the battery life is awesome for everyday use, but usually does need a charge every other day or so.
On the Ultra 4, the battery is a standout. One of the reasons it’s so big is because of the battery, which now lasts up to 50 hours. The Ultra 4 hasn’t died on me yet, plus it charges super fast. I put it on the charger for a few minutes at a time before bed and it goes up 30 percent.
Who Should Buy the Apple Watch Ultra 4 vs. Series 12
| Price | From $799 |
| Sizes | 49mm |
| Colors | Black or natural finish |
| Battery | Up to 50 hours of normal use or 84 hours in low power mode |
| Health and Fitness Features | Readiness score, health age, cycle tracking, heart rate tracking, irregular rhythm notifications, medications app, mindfulness app, noise app, sleep stages, sleep score, sleep apnea notifications |
| Price | From $399 |
| Sizes | 42mm, 46mm |
| Colors | Aluminum (dark bronze, light gold, black, space gray), titanium (radiant gold, natural), or ceramic (pearl white, night blue) |
| Battery | Up to 24 hours of everyday battery life and 15 minutes gives you up to 12 hours of additional battery life |
| Health and Fitness Features | Readiness score, health age, cycle tracking, heart rate tracking, irregular rhythm notifications, medications app, mindfulness app, noise app, sleep stages, sleep score, sleep apnea notifications |
To be honest, I’m completely obsessed with the Ultra 4, and now that I’ve tried it, I never want to wear any other Apple Watch version. However, at $799, in my opinion, you should only invest in an Ultra 4 if you’re a serious outdoors exerciser hiking and running trails where you need that off-grid navigation, satellite connectivity, and other features. Additionally, if you’re more of a casual everyday exerciser but you know you’ll wear it everyday, you like the bigger screen, and you have the budget, then go for the Ultra 4.
But if you just want to wear an Apple Watch casually for workouts, checking texts when you’re away from your phone, and you want it to blend into your outfits (and wrist) a bit better than a bigger watch, go for the Series 12. Either way, you’re getting a great watch—but you want to make sure it’s worth your money.
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Addison Aloian is the associate health & fitness editor at Women’s Health, where she writes and edits across the health, weight loss, and fitness verticals. She’s also a certified personal trainer through the National Academy of Sports Medicine (NASM). In her free time, you can find her lifting weights at the gym, running on the West Side Highway in New York City—she recently completed her first marathon, the 2025 New York City Marathon—and watching (and critiquing!) the latest movies that have garnered Oscars buzz. In addition to Women's Health, she’s made an appearance on the Oprah Podcast and her work has also appeared in Allure, StyleCaster, L'Officiel USA, V Magazine, VMAN, and more.
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