Smart rings have been a niche inside a niche in the wearables world for more than a decade. But in the last few years, they’ve enjoyed a renaissance as more attention and hype brought bigger names to the category. Finnish company Oura has been around longer than most and is now the class leader despite fierce competition. At the end of last year, Oura released the Ring 4 to address the flaws of its predecessor and keep ahead of its now many imitators. It’s easy to say that it remains a technological marvel, but harder to say if it’s worth a decent chunk of your hard-earned to get one.

Daniel Cooper for Engadget

89100Expert Score

Oura’s latest Ring is the best smart ring on the market. But its range of functions remains limited by its size and the fact that it’s a ring.

Pros

• More comfortable
• Better data collection
• Gorgeous, clean app

Cons

• Requires paid subscription to use basic hardware features
• I’m not sure why the paint jobs cost extra

$349 at Oura

Hardware

Oura put a lot of effort into nipping-and-tucking the Ring 4, like ditching the epoxy resin interior for a full titanium body. The Ring 3, especially once it moved beyond its squared-off side, already looked like a fashion ring, and the Ring 4 continues in that vein. I wear my Oura Ring on my left index finger with a Vitaly Grip ring on the right to balance the look. And nobody can tell the difference between the two, which is just how it should be.

Unlike a watch strapped in place, rings have a knack of turning on your finger through the day. To combat this drift, Oura’s previous rings housed their sensors in raised domes on the inside surface to maintain contact with your flesh. I never found them uncomfortable, but it was an issue for some, which is why Oura has worked to re-package the sensors to fit flush. In lieu of that, there’s now an ugly-ass notch on the ring to indicate the side that should be facing your palm at all times.

Since it’s easy for the sensors to be out of alignment, you’re constantly at risk of poor quality data or, worse, gaps. Oura upped the number of signal pathways from eight on the Ring 3 to 18 here in order to maximize data collection. Plus, a new algorithm hunts for the most efficient way to pull data from those sensors to hopefully ensure gaps are a thing of the past.

The Ring 4 is available in a wider number of sizes than its predecessor, fitting fingers from size 4 to 15. With a re-engineered ring comes a re-engineered charging dock that’s a lot nicer, too. Unfortunately, it’s also slightly bigger and heavier, which is a burden when you’re taking the ring on a trip lasting longer than seven days.

If you already own an Oura Ring 3, then I’d say that while the Ring 4 is nicer, more comfortable and more useful, it’s not so compelling to make you ditch an existing unit in good working order.

In use

One downside of Oura’s iterative update is that much of what I wrote about the Ring 3 remains true about the Ring 4. Once it’s on your finger, it should very quickly fade into the background of your day, and it’s plenty easy to forget. Naturally, you’ll do all of your interacting with the ring via its mobile app, which is one of the best available for a smart ring. You’ll get regular notifications telling you how far through your daily activity goal you are, plus advice on when to get ready for bed. It’ll also send the occasional reminder to get up and move if the ring feels you’ve been sitting for too long.

Open the app and you’ll first be presented with a row of numbers showing your Readiness, Sleep, Activity, Heart Rate and Stress scores. Scroll down and you’ll get panes with more information about your activity goals, stress metrics and heart rate. If there’s an issue, you’ll also get additional commentary about the problem and suggestions on how to improve. For instance, my resting heart rate dropped in the late evening because I’d gone to town on a very big bag of Doritos. The ring knew, and told me that if I kept eating close to my bedtime, I’d ruin the quality of my sleep.

Keep scrolling and you’ll find your activity timeline, based on what the ring thinks you’ve been up to that day. Sadly, in my experience the system will frequently assume you’re exercising when it sees movement plus an elevated heart rate. It’ll often accuse me of doing some form of rigorous workout when, in reality, I’m just going up and down stairs while I get my kids ready for school. If you’re doing one type of activity, then it’ll pick it up as such but if you’re chopping and changing — for instance by doing circuits — then it’ll be labeled as “other.” If, in fact, it gets labeled at all: I have had instances where walking to and from my gym was recognised, but nothing I was doing when I was actually working out counted.

The app has a number of hidden depths, including the Explore section which hosts a small library of meditation content. There’s also Oura Labs, which is where the company shares its not-ready-for-prime-time features before they’re added to the platform proper. At present, the company is testing Oura Advisor, a conversational AI that gives you the same advice the app would anyway, just in a chat box format. It’s also testing an AI-based food-tracking algorithm that’ll discern what you’re eating from a picture of your meal.

We’ll get into the economics of this down in the Price section, but Oura paywalls a number of key features behind its Membership program. If you don’t cough up, you won’t get 24/7 heart-rate tracking, temperature monitoring, menstrual cycle insights, SpO2 and VO2 Max analysis. All of these features are essential if you’re looking to get even the basic use out of your Ring 4.

As for battery life, I wear a size 10 ring and over the last two months I’ve fairly regularly wrung seven days out of the device before I’m advised to find a charger. Naturally, the bigger rings have a bigger battery, and so your mileage may vary, but the company is promising “up to” eight days.

Having lost a significant amount of weight in 2024, I would often find my Ring 3 sliding clean off my finger. Thankfully, if your ring is paired with your smartphone, you’ll now be able to see its last-known location through the app. Unfortunately, this is just using your phone’s GPS, so while you’ll be able to know if it’s in your home (or further afield), it’s no help finding which couch cushion it fell under. Consequently, it’ll still be worth picking up third-party developer Andreas Assermark’s Find My Ring app, which will use the Bluetooth signal strength to help you pinpoint its location.

Tracking activity, sleep and stress

I’ve never believed wearables, or any consumer-grade health device, can or should be held to the same standard as a clinical model. The smarter approach is to trust the trend and look for patterns rather than obsess if you did 10,000 or 10,001 steps in a day. Especially as, for most people, if you’ve had a rough night or you’re feeling like hell, you probably already know.

What Oura offers is a lot of data which, if you’re not happy with a single aggregate score, you can drill down into. Thanks to a British Airways snafu, I wasn’t able to get my intended flight out to CES on January 4 and was waitlisted for the following day. That was a pretty stressful time given I’d be letting the Engadget team down on a pretty crucial and busy week. Looking at the data now, I can see my resting heart rate spiked on Saturday and didn’t settle for a few days.

Oura also provides a metric for Daytime Stress, which aggregates your heart rate, HRV, motion and body temperature through the day. What’s interesting is that even if the ring is keeping an eye on my heart rate, there are several instances where it stops collecting stress data. For instance, that stressful Saturday, my heart was racing but there’s no Stress metric from 7:45 to 11:15. A few days after I had some distressing personal news and while my heart rate spiked to 158bpm, the stress metric disappeared entirely.

I’ve already griped about the issues with automatic activity detection, even if it gets the bulk of its calls correct. I am often vexed, however, that it’ll often have a delay between you starting an activity and it beginning to track it. For instance, one of my regular lunchtime walks is to a local landmark 0.8 miles away from my home and back again. But often, the ring won’t notice that I’m out for a walk until I’m a way down the road, curtailing my stats, even if it has my phone’s GPS to help.

These are minor gripes but ones worth knowing if you’re thinking about using the ring for more intensive insights. Nobody in their right mind would think about buying a smart ring in place of a smartwatch, but be aware the data you’ll get is not perfect.

There’s one thing that I’m very intrigued by, even if I’m not in a position to test it right now, which is the recent tie-up between Oura and (Diabetes biosensor company) Dexcom. The partnership, announced November 2024, will see the two companies share data between their respective platforms. Plus, Dexcom has put $75 million behind the ring maker, pushing its valuation north of $5 billion.

Price and the Competition

The Oura Ring 4 is available for $349 if you opt for the default silver or black colorways. Should your taste extend to brushed silver or stealth, then you’ll need to pay $399, while the gold or rose gold paint jobs are $499. Before you buy, you’ll need to order a sizing kit — the existing sizing kits are not compatible with the Oura 4 — and are available in Size 4 through 15.

As explained earlier, key features aren’t available for use unless you pay $5.99 a month or $70 a year for Oura Membership. Oura has been charging this fee since the launch of the Ring 3 and is, for now, a key plank of its business model. Now, plenty of companies will sell you their hardware and paywall off additional features for you to subscribe for afterward. I suspect the reason the Membership rankles so many people is that the features held back aren’t just nice to have, they’re essential.

On a pragmatic level, small hardware businesses can’t survive without the lifeblood recurring revenue from existing customers brings in. $70 a year is, to be blunt, your insurance ensuring that Oura doesn’t go belly-up, turning your smart ring into a dumb one. Oura has been good at regularly adding more features to its platform, and allowing users to beta test them in Labs on the way. Plus, the company has been working with academics to help refine its data collection and prove its methods are sound.

But the approach of charging for what should be basic features is always likely to rankle the users. And it gives Oura’s rivals, which may not be as well-equipped, an easy stick with which to beat the current market leader. Samsung’s Galaxy Ring isn’t as good as Oura, but it retails for $400 without any additional monthly charges. Ultrahuman, Circular and RingConn all boast they won’t charge you extra to use their ring’s hardware and software features.

Wrap-up

The Oura Ring 4 is a stellar piece of hardware, an engineering marvel and a useful companion as you go about your day. If I sound like I’ve been nitpicking, it’s because the overall package is so good that it’s hard not to focus on the specs of dirt on the otherwise clean plate. The ring and its companion app are well-developed and muscular, offering a useful way to sum up your day. If you’re looking to buy a smart ring, then there’s little need to explore the wider market unless you are particularly predisposed to buying a Samsung.

If there’s a downside, it’s that Oura remains forever constrained by the limitations a smart ring imposes. As I wrote last year, there’s only so much data you can collect reliably from such a small device worn on the finger. Not to mention, they’re designed to fade into the background of your life, keeping an eye on your vitals and offering some post-facto tips. If you want something more comprehensive, then it’s likely a smartwatch is a better option, but for everything else, there’s this.