Best smart rings of 2025: We tested Oura, Samsung, Ultrahuman and Amazfit (2025)

Smart rings are revolutionising the world of wearable technology, offering a compact and stylish way to track health and wellness metrics without the bulk of a smartwatch.

These innovative devices are designed to monitor vital signs such as heart rate, heart rate variability (HRV), sleep patterns, blood oxygen levels (SpO2), body temperature, activity levels, sleep tracking and menstrual cycle tracking. As the market for smart rings continues to grow, major players like Oura, Samsung, Ultrahuman, and Amazfit are competing to be the best on the market.

Whether you're looking to improve sleep, track fitness progress, or gain deeper health insights, a smart ring can be a powerful tool. But with so many options available, how do you choose the best one? This Women's Health guide explores what smart rings do, their key features, and how they compare to other wearables, helping you find the perfect fit for your health and lifestyle needs.

A smart ring is a compact, wearable device designed to track various health and wellness metrics. Unlike bulkier wearables like smartwatches, smart rings are lightweight, unobtrusive, and stylish, making them an appealing option for users who want continuous health monitoring without a screen or extra bulk.

These rings use advanced sensors to track metrics like heart rate, heart rate variability (HRV), body temperature, sleep patterns, blood oxygen levels, and activity levels.

Smart rings function as stylish health trackers, providing real-time insights into key physiological metrics. Depending on the model, smart rings can monitor:

• Heart rate and HRV: Indicators of cardiovascular health and stress levels.
• Sleep tracking: Including sleep stages (light, deep, and REM sleep) and sleep efficiency.
• Blood oxygen (SpO2) levels: Useful for detecting issues like sleep apnea.
• Body temperature: Important for menstrual cycle tracking and overall health monitoring.
• Activity levels: Step counts, movement patterns, and exercise intensity.
• Recovery metrics: Readiness scores that help users gauge how well their body is recovering.

These features make smart rings a versatile tool for those seeking a more holistic view of their health.

Testing these smart rings was a group effort, with four members of the Women's Health team testing out a different smart ring. The testing length varied but they were each worn for a minimum of a month but often longer, with the Oura Ring and Ultrahuman Ring both being worn by the tester for a few months now.

When trialling these rings, the testers reviewed how well the ring lived up to the brand's overall claims, how user friendly the ring was and general pros and cons of wearing the ring.

Now that you know exactly what a smart ring is, what they can do and how we tested them, it's time for a deep dive into four of the most popular options on the market.

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As a longtime fan of the Oura Ring, I was eager to test the Oura Ring 4. After four months of wear, I can confidently say it’s a refined and improved version of its predecessor the Oura Ring 3.

The biggest upgrade is Smart Sensing technology, which adapts to your finger for more precise tracking. Sleep and cycle tracking are noticeably more accurate, and the ring now features recessed sensors for a more comfortable fit. It’s also thinner, lighter, and offers an expanded size range. Battery life has improved, lasting up to 8 days, and the redesigned charging port is easier to use.

Oura continues to excel in sleep tracking, offering deep insights into sleep stages, readiness scores, and trends. Cycle tracking is another standout, using body temperature fluctuations to predict menstrual phases with impressive accuracy. Other key features include heart rate monitoring, guided meditations, stress tracking, and a symptom radar that detects early signs of illness.

The Oura app is intuitive, providing easy-to-understand data breakdowns and personalised insights. The ability to track long-term trends makes it a great tool for optimising sleep, recovery, and overall wellness. However, activity tracking remains basic, and the subscription fee adds to the already high upfront cost. The ring also scuffs more easily than the Oura Ring 3, which may be a downside for those who prioritise durability.

The Oura Ring 4 is a top-tier smart ring, particularly for sleep and cycle tracking. If detailed health insights matter to you, it’s one of the best wearables available.

Read more: Oura Ring 4 review

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Lightweight, slim and available in three colours (gold, silver and black), the Samsung Galaxy Ring, while an investment, is a sound one. With no subscription fee to pay (unlike the Oura), your one-time purchase grants you access to a huge breadth of health and fitness tracking features, stats and reports.

The Samsung Ring tracks your activity, sleep, stress, heart rate and menstrual cycle, then employs a clever AI algorithm to analyse all that data and generate personalised insights, tips and suggestions — all with an aim to improving your wellbeing. Each day you’re met with an energy score, which is essentially your readiness, or battery level, for that day. This is pulled from your sleep score, recent activity levels and heart rate and forms the basis of your recommendations — so you know when you have the resilience to push yourself, and when you should prioritise recovery.

The sleep tracking in particular is impressive, with insights including sleep stages, blood oxygen level changes and your sleep score (made up of your overall sleep time and number of sleep cycles you went through, plus other biometric data). You can even check how much you snore and access sleep coaching, which determines your sleep animal (rather than chronotype). There are eight in total, including nervous penguin, sensitive hedgehog and exhausted shark — ouch.

On the quibbles front, there aren’t many, but one that will discount any Apple user is the fact that the Samsung Ring is only compatible with Android. Otherwise, we found the fact that you can’t log periods of sickness a big omission, and because you enter your daily target as a blanket goal, this doesn’t adjust each day according to your energy score, which seems odd.

That said, this is a brilliant smart ring and the no-subscription model is a real bonus. It’s comfortable to wear and looks good too — it’s nowhere near as obviously a wearable as some other options. We loved just how many workouts you can record in real time (yoga, finally!), and there are simple graphics you can glance at throughout the day that give you an overview of your activity levels, including step count. The battery life is excellent, as is the portable charging case (making it great for travel), and the associated Samsung Health app is easy to navigate. If you’re already a Samsung user, this is a no-brainer.

Read more: Samsung Galaxy Ring review

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With so many fitness tech gadgets on the market, we were curious to try the Ring Air from Ultrahuman—a brand we hadn’t heard of before. Right away, a major plus: unlike many competitors, it’s a one-time purchase with no subscription fees. The Ultrahuman ring tracks sleep, menstrual health, stress, heart rate, sun exposure, and dynamic recovery (to name a few) delivering a comprehensive weekly report. Uniquely, you can also chat or jump on a call with the Ultrahuman team to dive deeper into your data.

At just 2.4g, it's one of the lightest tracking rings we’ve tested (nearly half the weight of the Oura’s 4.6g) and comes in five stylish colours. A sizing kit ensures the perfect fit, and the minimalist and sleek design blends effortlessly with other jewellery.

The app is intuitive to use, offering clear insights and frequent updates, plus optional ‘Powerplugs’ to track extras like Vitamin D, screentime, caffeine windows, and pregnancy insights.

Downsides? Activity tracking isn’t always accurate, sometimes misjudging intensity. However, the app clearly states this feature is still in Beta, which we appreciate for transparency.

Final verdict: if you want in-depth wellness insights – especially around sleep and recovery – this ring is a fantastic buy. We’re excited to see what Ultrahuman does next.

Read more: Ultrahuman Ring review

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The Amazfit Helio Ring is a lightweight smart ring designed for health tracking. Made from titanium alloy, it blends nice-enough style with a decent amount of function, offering insights into sleep, stress, and overall wellness – all without a subscription. It syncs easily with Amazfit’s ecosystem but has some notable drawbacks, especially with sizing and battery life.

With a subtle dot pattern, the ring looks good while packing in useful tracking features. It monitors heart rate, stress, and menstrual cycles, and the readiness score provides a useful gauge of energy levels based on sleep and activity.

The biggest drawback, undoubtedly, is the sizing. With just three options (‘8’, ‘10’ and ‘12’), a lot of people will simply struggle to make the ring fit – 12 being too big; 10 too small. ‘Stacking’ the Helio Ring underneath another conventional ring works to keep it secure, but that’s far from ideal. Battery life is another issue, lasting only 3-4 day – shorter than competitors like the Oura Ring – and the cradle-style charger isn’t the most convenient.

The Zepp app provides plenty of data but isn’t the easiest to navigate, and occasional connection issues can be frustrating. And without automatic activity tracking, you have to manually log workouts, which feels outdated.

Overall, this smart ring has potential, but its limitations make it a tough sell. If you already use an Amazfit smartwatch, it could be a good add-on – but as a standalone tracker, it’s got some catching up to do.

Smart rings are worth considering for users who prioritise discreet, 24/7 health tracking without the distractions of a smartwatch. They provide highly accurate physiological data while being comfortable to wear throughout the day and night.

That said, they may not be ideal for everyone. Users who want a device with built-in workout tracking, GPS, or notifications might find smartwatches more suitable. However, for those focused on passive health monitoring and long-term insights, smart rings offer tremendous value.

Almost every member of the Women's Health team wears a smart ring, whether it be the Ultrahuman, the Oura Ring or the Samsung Galaxy ring. As a health-conscious group of people, we like to be able to keep an eye on our health data and far prefer wearing a ring than a smartwatch.

What finger should I wear a smart ring on?

While all the rings we tested can technically be worn on any finger, each of the brands recommends wearing it on the index finger of either hand for the best accuracy.

How do smart rings compare to other wearable health devices?

According to Dr Greg Potter, sleep expert and researcher, 'there doesn’t seem to be much daylight between the sleep tracking accuracy of the best smart rings and the best wrist-worn sleep trackers.'

In saying that, he added that 'perhaps the biggest pro of smart rings is their form factor – they’re barely noticeable, and the fact the fit is snug is a good thing when it comes to the accuracy of their sensors.'

However, he notes that wrist-worn devices typically offer a broader range of features due to their larger hardware. Chest straps, which are worn directly over the heart, tend to provide the most precise heart function metrics.

Dr Shyamel Patel from Oura adds that smart rings measure data directly from the arteries in the finger rather than capillaries on the wrist. 'This enables the rings to capture the signal as it leaves the heart, rather than on a delay on the return, therefore making the data more accurate.'

What are the most important health metrics a smart ring should track for Women's Health?

Dr Patel emphasises the role of temperature tracking for women’s health. 'Body temperature variations, due to fluctuating hormones, provide crucial insights into menstrual tracking and reproductive health.'

Tracking body temperature allows smart rings to predict ovulation and detect cycle irregularities. Other important metrics include:

• Heart rate and HRV: Hormonal changes impact cardiovascular health.
• Sleep patterns: Sleep quality often shifts during different menstrual phases.
• Stress and recovery: Chronic stress affects reproductive health and overall wellbeing.

What key features should we look for when choosing a smart ring?

Dr Patel advises that consumers should consider their specific health goals first. 'For some of us, that could be improving sleep, for others it could be trying to conceive.'

Key factors to consider include:

• Accuracy of sensors: Look for devices validated by scientific research.
• Battery life: Most smart rings last between 4-7 days per charge.
• App experience: A well-designed app is crucial for interpreting data.
• Temperature tracking: Important for cycle tracking and recovery insights.
• Third-party integrations: Compatibility with health apps like Apple Health and Google Fit.

Do smart rings work better than period tracking apps for predicting ovulation?

Dr Patel highlights research showing that Oura’s ovulation tracking outperforms traditional calendar-based methods. A recent study published in the Journal of Medical Internet Research found that 'Oura detected 96.4% of ovulations with an average error of ±1.26 days, and was significantly more accurate across all cycle lengths and age groups than the calendar method.'

Additionally, Oura integrates with Natural Cycles, allowing users to track their cycle without manual temperature logging. Samsung is also integrated with Natural Cycles and uses a similar technology to predict ovulation.

Which smart ring has the most reliable data?

According to Dr Potter, 'The different generations of the Oura Ring have been the most-studied smart rings, generally performing relatively well compared to other wearable and wearable sleep trackers.'

While other brands like the Ultrahuman Ring, Samsung Ring, and Amazfit Ring are emerging competitors, Oura remains the gold standard in terms of research-backed accuracy.

How do smart rings measure body temperature, heart rate, and blood oxygen levels without a display?

Smart rings use an array of sensors to gather physiological data:

• PPG (Photoplethysmography) sensors: Measure heart rate and SpO2 using infrared light.
• Skin temperature sensors: Detect variations for cycle tracking and illness detection.
• Accelerometers: Track movement and sleep patterns.

Unlike smartwatches, they rely on an app for data visualisation, reducing distractions and battery consumption.

Check out more fit tech reviews here:

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• I’m a PT who's tested dozens of smartwatches, here’s why I keep coming back to the Apple Watch Series 10
• WHOOP review: ‘I’ve been wearing a WHOOP band for over a year, here’s why it’s not just a tracker for elite athletes’