By: Ella Carter
Product Reviewer, Sleep Tech
Updated June 26, 2026 • 7 min read
If you’re deciding between the Oura Ring 5 and Oura Ring 4, you’re already looking at two of the most trusted smart rings for sleep tracking. The Oura Ring 4 built its reputation on accurate sleep insights, strong health tracking, and one of the most refined wellness apps available today.
The Oura Ring 5 doesn’t change that foundation. It refines it. The sleep data you see each morning is almost identical, but the experience of wearing the ring is noticeably different. It is slimmer, lighter, and easier to forget overnight, which makes it a stronger everyday option for many people.
This article focuses on how the two rings compare. If you’d like a more in-depth look at the Oura Ring 5, including its design, comfort, sleep tracking, and everyday experience, read our full Oura Ring 5 Review.
Key Differences at a Glance
Oura Ring 5:
- Best For: New buyers
- Comfort: 40% smaller, slimmer feel
- Sleep Tracking: Excellent (same core data as Ring 4)
- Women’s Health: Excellent (same core features as Ring 4)
- Battery: 6–9 days (better than Ring 4)
- Sizes: 6–13
- Sleep Scoop Pick: Best Overall Sleep Tracker
Oura Ring 4:
- Best For: Existing owners & deal seekers*
- Comfort: Thicker, more noticeable on the finger
- Sleep Tracking: Excellent (same core data as Ring 5)
- Women’s Health: Excellent (same core features as Ring 5)
- Battery: 5-8 days
- Sizes: 4-15
- Sleep Scoop Pick: Still a great sleep tracker
Should You Buy the Oura Ring 5 or Oura Ring 4?
If you’re buying your first Oura Ring:
Go with the Oura Ring 5 if you want the slimmer, lighter design that feels more like jewellery and is easier to wear overnight. Choose the Oura Ring 4 if you prefer a slightly thicker ring or find it at a good discount right now. It still delivers excellent sleep tracking and overall performance.
If you already own the Oura Ring 4:
Stick with the Ring 4 if it already feels comfortable and you’re happy with your sleep data. The core sleep tracking experience is very similar between both models. Upgrade to the Ring 5 if you love the Oura experience but want something that feels lighter, more subtle, and easier to forget you’re wearing at night.
How Does the Oura Ring 5 Compare to the Ring 4 for Sleep Tracking?
The sleep tracking experience is remarkably similar on both rings. You’ll still see Sleep Score, sleep stages, heart rate variability (HRV), overnight blood oxygen, temperature trends, bedtime guidance, and the other core insights that have made Oura one of our favourite sleep trackers.
Where the Ring 5 differs is in how it collects that data. According to Oura, redesigned sensors, stronger LEDs, and a new sensing system allow the ring to sit closer to the skin while maintaining accuracy. In theory, that could help reduce movement interference and support cleaner overnight readings. We’ll be watching to see whether that translates into a meaningful real-world difference as more long-term testing becomes available.
For most people, though, I think there’s an even more important takeaway. The best sleep tracker isn’t simply the one with the newest hardware. It’s the one you’re happy to wear every single night without thinking about it. From what I’ve seen, that’s where the Ring 5 quietly pulls ahead, which is why we now consider it our Best Overall Sleep Tracker for most people.
How Does the Ring 5 Compare for Women's Health?
Much like sleep tracking, the core women’s health features remain the same on both rings. Cycle Insights, Period Prediction, and integrations with apps like Natural Cycles, Flo, and Clue are all available on both the Oura Ring 4 and Ring 5, using overnight temperature trends to provide personalized insights throughout your cycle.
The biggest difference is, once again, wearability rather than new features. A ring that feels lighter and less noticeable may be easier to wear consistently, and consistent overnight data is what helps Oura build a more complete picture of your cycle over time.
What Does the 40% Smaller Design Actually Feel Like?
Oura describes the Ring 5 as the world’s smallest smart ring and says it’s 40% smaller than the Oura Ring 4. Looking at the specifications, that sounds like a big change, but it wasn’t until I felt the difference that I could really appreciate what it means.
When I compared the same ring size in both kits, I was surprised by how much slimmer the Ring 5 looked and felt. It feels noticeably less like wearable technology and more like a ring I’d happily wear every day.
Comparison photo coming soon (Comparing the Oura Ring 4 and Oura Ring 5 sizing kits in the same size. The Ring 5 has a noticeably slimmer profile while maintaining a similar fit.)
The size difference won’t matter to everyone. But if you’re like me and you’ve felt like some smart rings feel too bulky or look too much like a gadget, I think you’ll immediately understand why Oura made this change.
Our Recommendation
The Oura Ring is still one of the best sleep trackers available. It delivers detailed sleep insights, strong recovery data, and one of the most refined health apps in the category.
The Oura Ring 5 is a clear refinement of that experience. It keeps the same excellent sleep and wellness tracking Oura is known for, but delivers it in a noticeably smaller, lighter, and more comfortable design. For many people, that alone makes it a better everyday choice, especially if comfort or wearability has ever been a concern.
That’s why we now recommend the Oura Ring 5 as our Best Overall Sleep Tracker for most people. If you already own the Ring 4 and are happy with the size and feel, there is no urgent need to upgrade. But if you are buying your first Oura Ring, or want the same tracking experience in a more discreet, jewellery-like form, the Ring 5 is the version we would choose today.
Want a closer look? Read our full Oura Ring 5 Review for detailed testing, features, and everything you should know before buying.
Frequently Asked Questions
Yes, as long as you're comfortable with the larger size, the Ring 4 is still one of the best sleep trackers available. It offers the same core sleep, recovery, and women’s health insights as the Ring 5, and it's still an excellent option (especially if you find it at a lower price).
Yes. The Ring 5 uses a redesigned sizing system, so you should use the Oura Ring 5 sizing kit even if you already know your Ring 4 size. In some cases, you may find that your Ring 5 size is different from your Ring 4 size.
No. The Ring 5 uses a redesigned charging dock and is not compatible with the Ring 4 charger.
Oura generally recommends the index finger as the best option because it tends to provide the most stable readings. The middle or ring finger can also work well as long as the fit is snug and the ring does not rotate during sleep.
If you’re still comparing options, you can also see how these trackers stack up against other top picks in our Best Sleep Trackers of 2026 guide.