The best smart ring I've tested blows the competition out of the water

ZDNET's key takeaways

The Oura Ring 4, the newest generation of the popular smart ring is now available to buy and starts at $350 The Oura Ring 4 emphasizes a comfortable build with flatter and smarter sensors, more sizes, upgraded software, and an alleged eight-day battery life The eight-day battery life is actually more like five and a half days.

While Oura was quiet these past few years, in between the release of its Ring 3 in 2021 and the development of its Ring 4 (now available), a groundswell of competitors released smart rings of their own, from big-name brands like Samsung to indie upstarts like Ultrahuman. 

Also: The Oura Ring 4 rolls out with a thinner design and more sensors and sizes

The smart ring space is heating up, and we have officially reached peak health tech wearables. During the past few years, Oura has been busy developing a smart ring that's smarter and stronger than the rest: the recently unveiled Oura Ring 4. I've tested the device over 10 days, and it surpasses the competition by a mile. Keep reading to learn why. 

Oura puts comfort at the forefront of its Ring 4 -- both functional comfort, being great to wear, and via extended and inclusive sizing. Oura's Ring 3 offers sizes six through 13, and the Ring 4 offers sizes four through 15. 

I've worn the Gen 3 since January, and I regularly noticed dry spots around my finger where the protruded sensor domes left impressions. This made the device irritating to wear for longer periods. The Ring 4 uses receded smart sensors to keep the inside of the ring flat and easy to wear, creating the most comfortable and unnoticeable generation of the device yet.

As annoying as they were, the Ring 3's protruded sensor domes did tend to grip your finger, which made it easier for the ring to stay secure while you were asleep, and for the position of the dimple to stay set on the inside of your finger, where it collected the most accurate data. Without the domes, the Ring 4 becomes slippery: the second night I wore the ring on my pointer finger to bed, it fell off while I was asleep, something that never happened during my nine months with the Ring 3. 

Also: The best smart rings you can buy

A major selling point that intrigued me with the Oura Ring 4 is the extended and uber-competitive eight-day battery life. I hadn't seen any competing smart rings with such a long battery life, so I was eager to see how long the device would last. I put the ring on at 9 am on a Friday morning, and somewhere between Wednesday night and Thursday morning, the ring hit 0% and died on me. 

That battery life clocked in at about five days, three days less than advertised. Most batteries don't last as long as advertised for regular wear. For example, Samsung's Galaxy Ring advertises a seven-day battery life but regularly lasts four to five days, tops. Nevertheless, I hoped the Oura Ring 4 battery life would have endured a few more nights of sleep before dying. 

On the bright side, recharging the ring took no time and boosted the battery from 0% to 30% in less than 20 minutes.

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Another major selling point of the Oura Ring 4 is its smart sensors, which keep the build comfortable and its battery life long. Oura adds 10 extra signal pathways, making 18 in total to gather health data and adjust for the natural movements of the ring that occur during daily wear. The smart sensors are supposed to make the data capture process more accurate and continuous, but I can't confirm that feature right now. I'll compare the smart ring to other favorites in the coming weeks, so stay tuned for those articles. 

Hardware aside, the software inside the app is as intriguing and updated as the physical ring itself. Some of my favorite features Oura improves upon in its fourth-generation device include the automatic heart rate monitoring that takes place through its workout detection feature, the meal-logging functionality that correctly cataloged my slop of a breakfast (more on that later), and the daytime stress feature that offers more context than ever. 

Also: Oura Ring 3 vs. Apple Watch: Which should you buy? 

Let's start with heart rate monitoring. Before the Ring 4 upgrade, if you wanted to capture data on your heart rate while exercising, you'd have to go into the app to hit record on that function. The upgraded app -- available to all Oura users, regardless of smart ring generation -- takes this data automatically when it detects movement. When dancing at a concert one night, the device automatically clocked the activity and recorded my heart rate. I love any feature upgrade that does the busy work for me, so I can spend less time thinking about recording my activities and more time doing the activity itself (and reviewing the data later).  

The second software feature that blew me away was meal logging. The first morning I tried out the feature, available to test out through Oura Labs, I was half-finished with my yogurt, chia seeds, banana, and raspberries. I picked over the breakfast because I realized halfway through that I wanted to log the meal. This decision was no problem for the AI camera, which detected almost every ingredient in my bowl, to my utter surprise and disbelief. You can't count calories with this feature; instead, it's a way to log the timing of your meals to understand how regularity impacts your vitals over the day. Meal logging is an experimental feature and could disappear in time, but it's a helpful and impressive tool that utilizes AI cleverly and surprisingly. 

Also: Oura surpasses Apple Watch and Fitbit's sleep accuracy in recent study 

Lastly, Oura upgraded its daytime stress feature by including the tags users add throughout the day and the exercises it automatically detects and overlays on the daytime stress timeline. The overlaid timeline clarifies and distinguishes between bodily stress caused by a hard workout or stress caused by a day at work or a social outing late at night. 

The launch of the Ring 4 also brings the Oura app redesign. Given the smart ring is screenless, the user experience relies on an effective app with great data illustration. Oura has redesigned the interface to create three core tabs: Today, Vitals, and My Health. The Today tab provides a snapshot of your daily scores and health data, like readiness, sleep, activity, heart rate, and stress duration. The Vitals tab shows you a historical view of those scores. The My Health tab shows trends that don't change over a week or two, like your resilience level, cardiovascular age, and sleep health. 

The layout is a thoughtful way to separate the many datasets Oura records into relevant-by-day, relevant-by-week, and longitudinal illustrations. Some metrics are harder to find through this reorganization than others. Reddit users have already shared their critiques of the redesign, with many opposing these changes (it's a universal tech truth that users rarely welcome an app redesign). With some curiosity and patience, you can still find the data you're looking for on the app -- trust me. 

Also: How we test smart rings at ZDNET in 2024

As usual, you learn lots about your body simply by having this thing around your finger, such as how much better you sleep when you haven't drunk alcohol or eaten late into the night, and how your body reacts to the daily stresses of being a human. That capability hasn't changed from ring generation to generation. 

Another thing that, unfortunately, hasn't changed is that this device will still cost you a lot of money -- and you will still have to pay a monthly subscription (despite smart ring competitors doing away with subscriptions of their own). The Oura Ring 4 starts at $350 and rises depending on your desired finish. You'll also pay $6 monthly if you want access to all the data the ring gathers. 

ZDNET's buying advice

So, should you buy it? Most of the hardware upgrades prioritize comfort, so, if you already have an Oura Ring 3, I'd only buy the Oura Ring 4 if you can't stand the uncomfortable protruded dome sensors of the earlier generation. Much of the impressive software is coming to both models through the app. Another reason to buy the new ring could be the (somewhat) extended battery life, if your Ring 3's battery is withering away, and the expanded sizing if you haven't found a smart ring that fits your finger. 

If you haven't purchased a smart ring yet, I'd recommend the Ring 4. Despite its competitors vying for attention, there's no question which company is winning the smart-ring race -- and it's the Oura Ring 4. No smart ring is as innovative, feature-rich, size-inclusive, and thoughtful in its design and rollout.