Oura Ring 4 Sizing Kit - Size Before You Buy The Oura Ring 4 - Unique Sizing, Not Standard US Ring Sizes - Receive Credit for Purchase
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Availability:
Only 3 left in stock, order soon!
Arrives
Sunday, Sep 21
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Color: Sizing Kit
Size: Sizing Kit
Features
- SIZE BEFORE YOU BUY - Oura Ring 4 sizes are different from standard ring sizes. Size yourself with the Oura Ring 4 Sizing Kit. For additional details, see From the brand section below
- NOT STANDARD SIZING - Oura Ring 4 sizes are slightly different from standard ring sizes, so it is important to size yourself using our Oura Ring 4 Sizing Kit. Oura Ring 4 is available in sizes 4-15. There are no half sizes
- COMFORT AND ACCURACY - A properly fitting Oura Ring will result in the highest data accuracy, comfort, and overall experience
- CHOOSE A FINGER - Oura Ring 4 works on all fingers and can be worn on either hand. For optimal accuracy, we recommend wearing your Oura Ring 4 on your index, middle, or ring finger. Size the exact finger you plan to wear your Oura Ring 4 on
- HOW IT SHOULD FIT - Oura Ring 4 should fit securely and comfortably at the base of your finger. Your ring should not rotate as you go about normal daily tasks. We recommend wearing your ring sizer for at least 24 hours to confirm your best fit
Description
The Oura Ring 4 Sizing Kit allows for you and those around you to find the ideal fit before purchasing. With a sizing kit purchase, a 10 credit will automatically be applied to your Oura Ring 4 at checkout. A properly fitting Oura Ring 4 will result in the highest possible data accuracy, comfort, and overall experience. Oura Ring 4 sizes are slightly different from standard ring sizes, so it is important to size yourself using our tools and to follow our sizing instructions. Oura Ring 4 works on all fingers and can be worn on either hand. For optimal accuracy, we recommend wearing your Oura Ring 4 on your index, middle, or ring finger.
Package Dimensions: 6.61 x 4.41 x 0.47 inches
Item Weight: 1.83 ounces
Item model number: JZ98-54870
Other display features: Wireless
Color: Sizing Kit
Whats in the box: Oura Ring 4 Sizing Kit
Manufacturer: Oura
Date First Available: October 3, 2024
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Sunday, Sep 21
- Klarna Financing
- Affirm Pay in 4
- Affirm Financing
- Afterpay Financing
- PayTomorrow Financing
- Financing through Apple Pay
Learn more about financing & leasing here.
Similar Products
Top Amazon Reviews
Color: Silver
Size: 6
I’ve been using my Oura Ring for a month now, and I’m genuinely impressed. It’s sleek, lightweight, and easy to forget you’re even wearing it which is exactly what I wanted in a wellness tracker. The sleep tracking is incredibly detailed and has helped me better understand my sleep patterns. I’ve started making small changes to my routine based on my readiness scores and have noticed a real difference in my energy levels. I also appreciate the insights on recovery, heart rate, and activity without the bulk of a smartwatch. The app is user-friendly and the daily reports feel like a personal check-in. The only thing to note is that sizing can be a bit tricky – I used the sizing kit before ordering and I’m glad I did. Battery life has also been solid; I only charge it every 3-4 days. Overall, this has been a great investment in my health and well-being. If you’re looking for something subtle, smart, and science-backed, I highly recommend it.
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Reviewed in the United States on July 12, 2025 by Shantel B
Color: Stealth
Size: 14
So far, I’m very happy with my Oura Ring. I’m honestly surprised by how accurate it is—it really does a great job tracking my health and daily patterns. It’s comfortable to wear, the battery life is solid, and it charges quickly. Since I’ve started using it, I’ve noticed improvements in my health habits. The only drawback is that it does scratch a bit easily, but I work in construction, so that’s to be expected. One small quirk is that when you’re watching TV or working at the computer, it might log it as a nap due to lack of movement. Thankfully, you can easily dismiss those entries if they’re incorrect. Overall, I’d recommend it to anyone who wants an easy and effective way to track their health.
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Reviewed in the United States on August 10, 2025 by Amazon Customer
Color: Black
Size: 7
I’ve been supporting Oura since it was a kickstarter. I had the version 3 and decided not to upgrade but since my SO lost her ver 3 I gave her mine and ordered this. If you’ve never had an Oura ring: this product is amazing. So comfortable, more so than a watch. The app is great, I’ve learned so much about sleep habits, what to do and not to do for sleep. Lovers of science will like this, you can literally experiment and see the exact results for yourself. Accuracy: I would say this is 95% accurate. Again, I’ve been using this for about 5 years. So I’ve seen the accuracy improve IMMENSELY over the years. Version 4 is the best yet. Better than any other sleep tracker I’ve tried and I’ve tried a lot. The biggest inaccuracy is every now and then I’ll get up to pee in the middle of the night and it will think I woke up for the day. Sometimes it knows I just went to pee sometimes not. Since I noticed it, I take my ring off if I get up to go to the toilet and it fixes the issue—just don’t forget to put it back on! Key info for consumers: the fit is slightly larger than the version 3. To be exact I would say the version 4 is about half a size larger. So the new size 7 for example, would be a size 7.5 on the old version 3 and older models. The new size is great for me. My old ring was snug on my ring finger. So now I can wear the new one on my pointer finger and even middle finger depending on how hot it is. It all depends on the temperature outside due to our hands expanding/shrinking in heat/cold. Hot days I’ll wear on my ring finger, cold days I can wear on my index or middle finger. Conclusion: I love the Oura ring. It’s more comfortable than an Apple Watch or a woop in my experience. Way, WAY more comfortable. It’s also very accurate and the info is extremely useful. It’s increased my understanding of sleep, the importance of exercise for sleep, and dare I say, made me a better person. Getting better sleep takes effort, and this is merely a tool to help you do that. Getting better sleep can 100% make you a better person and I speak from my own experience.
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Reviewed in the United States on March 18, 2025 by Andrew McMillian
Color: Sizing Kit
Size: Sizing Kit
Amazon, despite complaints, views the Ōura Ring Sizing Kit as the same or a similar item as the Ōura Ring 4, itself... thus, two DIFFERENT reviews AND ratings for two COMPLETELY DIFFERENT products. -------------- 1) THE ŌURA RING SIZING KIT / 5-Stars Ōura states that the Ring 4 sizes are NOT the same as traditional ring sizes. I did NOT break out my Ring Sizing Loops to determine the veracity of that statement because the cost, of the Ring 4 Sizer, on Amazon is applied as a credit towards the cost of an Ōura Ring 4 WHEN purchased via Amazon. I will say that there is perhaps a little difference, compared to traditional ring sizes, but I'm not sure that it's much because I ended up with the ring size that I thought would work. Interestingly enough, size 10 that I expected for the middle finger was a perfect fit for the Index finger, which is normally a traditional 9... so there is some difference in the sizing and I wholeheartedly recommend procuring the Ōura Ring 4 Sizer BEFORE purchasing the Ōura Ring 4. NOTE that the Ōura Ring 4 Sizer does not work for all Ōura Ring models, so anyone deciding to purchase a previous iteration of the Ōura Ring, due to cost decrease and/or a Sale, will need to utilize the correct Ōura Ring Sizer for the model ring chosen. If there is a question of Sale or Discount Pricing, due to the delay from checking ring sizes, then I suggest an online Chat with Amazon Customer Service representative to make sure that you can lock in any discounts to use after verifying the correct Ring size. FYI - Ōura recommends wearing the sizing ring on the finger that will bear the ring, in order to become accustomed to the ring size/feel and to see how well it fits throughout a normal day. I followed that advice and I believe that everyone should do the same. ---------------- 2) Ōura Ring 4 / 1-Star First, even with the ring sizing kit and wearing the sizer non-stop until the Ring 4 arrived, the size of the Ring 4 in only whole sizes proved inadequate. My hands clearly fluctuate enough in size to be an issue, regardless of the finger or hand that is used. Next, the heart rate (HR) was always available and showing in the app, signifying that the Ring 4 was measuring the HR, HOWEVER, the app called to show the graph of the HR for over two (2) weeks, meaning there was no history nor any assessment available. Next, the Sleep function, even with learning curve, seemed to function out of the box, HOWEVER, after the first recharge of the Ring 4, there was an issue with accurately recording start and stop points of Sleep AND eventually the app would show No Sleep Data AFTER uploading/updating UNTIL THE NEXT day. There was no event showing for sleep ALTHOUGH the Ring 4 clearly annotated the Start of the Sleep period the previous night. Next, even after more than three (3) weeks of use, the app has failed to graph the Blood Oxygen Saturation, in spite of showing the data observed and available to see at any given moment. Again, I find this to be very odd and indisputably useless to the user. Next, the App is full of "flash" or substance but in terms of a quick overall view of all the numbers, like most Apps, no such uncluttered view can be found. While the plethora of information and links is appreciated, the search to locate immediate data numbers across all items is tedious, frustrating and unappreciated. To provide an analogy, it's like having to read an entire book to search for and locate the Synopsis of the book. For those who aren't into books, then it's like watching a TV and THEN SEEING the Preview for the show that you just watched. I and most users seem to prefer a Table of Contents approach where the Raw Data is shown and then you can click to go to the Analysis, Assessment and Suggestions for that particular Biometric. In short, the App's interface is beautifully flashy and showy but about as useful up front as a Show Pony on a crop farm. That makes it overwhelming, even to those who are focused readers and moreso to the vast majority who are not. Finally, many details and assessments are NOT available for anywhere from four (4) weeks to three (3) or more months. While understandable, it makes it impossible to fully assess the personal value and utility of the Ring 4 in the 30-day period for returns. That means that the $400+ ring and the annual subscription fee is only acceptable for those with money to burn, so to speak, because all of the shortcomings or issues, even if expandable and temporary, outweigh the cost of what is actually a pretty doggone accurate piece of tech wear, resulting in the clear choice to return the ring. AND... there is one other issue to consider which is that if your hands swell, perhaps from work, or shrink, perhaps from weight loss, then your $400+ ring AND subscription become useless... until you purchase another Ōura Ring that does fit. Based on my research and experience, there are equally accurate smart fitness watches with solid Apps and reasonable insights and suggestions based on the assessment of the biometrics. Also, there is another smart ring on the market that appears to rival the Ōura Ring in accuracy, provides an seemingly identical App for all appearances seen, comes as an adjustable ring using the same high-end materials and sensor setup AND which additionally boasts being approved and classified as a Medical Grade Device, instead of a Consumer Grade Device. All of that at a far, far lower cost AND the same updates, assessments, insights and suggestions BUT with NO subscription fee. That being said, I am a Go/No-Go tester of products meaning things are either 5-star or 1-star with enough details for people to decide that my 1-star item might be good enough to be their 3- or 4-star item. The Ring 4 failed to make the grade for my needs nor was it able to justify keeping the ring to see if things improved or the money was worth the extended wait for certain observations, but it was remarkably accurate when comparing data to manual results, such as HR, SpO2, etc. There is no blood pressure data, for those in search of BP function. I am not sure that BP could be accurately obtained below the wrist at this point in technology, but maybe in the future. REMEMBER that when returning an Ōura Ring, you MUST also CANCEL the Ōura App Subscription as it is a separate financial issue from the purchase. The subscription is free for the first 30-days and a part of setting up your account before you are able to use the App, so it's an easy thing to forget. 3) Addendum -- there is a charging cable organizer with a carabineer that works GREAT for the Ōura Ring 4 charging station and cable that is available on Amazon AND IS HIGHLY RECOMMENDED. That is my next review and it will be 5-Stars. It was kind of a why-the-heck-not afterthought purchase that became an INSTANT 5-Star Should Have item as soon as I unpackaged it!!!!
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Reviewed in the United States on March 21, 2025 by Avid Reader