Your complete guide to picking the right size Oura Ring

Smart rings are unique in the world of fitness trackers. Instead of wrist-worn devices with large displays and flexible straps, smart rings are more rigid bands made for wear on a finger. As a consequence of this design, smart rings usually require a measurement process before purchase, which is no less true with the Oura Ring. The right fit is vital for user comfort and fitness tracking accuracy. Here’s how to choose the right size Oura Ring.

Which finger should I wear my Oura Ring on?

Theoretically, you can choose to wear the Oura Ring on any finger, but Oura suggests wearing its rings on the index finger with the three sensor nubs on the palm side of your hand. This is true for the Ring 3 and Ring 4.

A notch on the outside of the ring makes it easy to orientate the device. The index finger should provide the best tracking accuracy, but it’s not always the most comfortable option unless you’re used to wearing rings on that finger.

How to choose the right size Oura Ring

Aside from choosing an Oura Ring model, picking the correct size is arguably the most important step in your smart ring purchasing journey. The Ring 3 and Ring 4 are available in slightly different sizes. Find the details below.

Ordering an Oura Ring size kit

Before ordering an Oura Ring, you must determine the best size for you. We suggest requesting a Free Sizing Kit in your Oura Ring order to aid your quest. The company will ship out the sizing kit first, allowing you to wear all sizes, pick the best for your circumstance, and confirm the size before your actual ring is delivered.

Alternatively, if you don’t fancy waiting for a sizing kit to arrive and own a 3D printer, you can print your own Ring 3 sizers using these official files. If you don’t have a 3D printer, you can purchase a sizing kit for the Ring 3 from Target or the Ring 4 from Amazon if you’re in the US.

Oura Ring size table

The Oura Ring 4’s sizing kit includes 12 plastic rings, ranging from 4 (the smallest) to 15 (the largest). This broader size scope makes the ring more sensible to wear on your pinky finger, even though Oura doesn’t recommend that. The new ring model also includes a slightly different internal design, with smaller sensor bumps. This means the two rings of the same nominal size will fit completely differently on the same finger.

The Oura Ring 3’s sizing kit includes eight plastic rings ranging from size 6 (the smallest) to size 13 (the largest). Based on our measurements of the Ring 3, these sizes are basically the same thickness, falling between 2.5mm and 2.9mm. In terms of height, all eight fall just short of 8mm. However, the critical measurement for fit and feel is internal diameter.

You can find the approximate internal dimensions of each Ring 3 size below.

The above table should be used as a guide, and we don’t recommend using the dimension chart to pick an Oura Ring size. If you don’t have time to wait for a sizing kit, measure the internal diameter of a ring you’re already wearing on your index or ring fingers and choose a similar Oura Ring size. We don’t quite recommend this, though, as nothing quite beats real-world experience. Additionally, a diameter that may seem too tight or loose on paper may give you the perfect fit in practice.

It’s worth noting that Oura does not offer half or custom sizes, nor do the rings conform to standard US sizes. For instance, a US ring size 6 has an inner diameter of 16.5mm, a fair bit larger than the size 6 Oura Ring.

While the Oura Ring 3 sizers are black, the Oura Ring 4’s sizes are white. This helps to differentiate the two if you own both.

Tips for picking the correct Oura Ring size

Even though the Oura Ring 3 and Ring 4 are sized differently, it’s important to to remember these points when choosing a size:

• Oura recommends that you pick a finger on which to wear the ring, then choose a size that feels best on that particular finger. However, we believe that testing the sizer rings on a few fingers is a better bet. This more thorough method will give you a better idea of how each ring size feels on multiple fingers and whether wearing it on one digit is more comfortable.
• If you usually wear other rings on your fingers, don’t remove them. This will give you a better real-world experience of wearing the Oura Ring alongside your usual kit.
• You should wear a sizer ring for at least 24 hours, taking into account body and temperature changes throughout the day. Wearing the sizers for longer should allow you to make a more informed decision.
• Go about your normal routine while wearing the sizer rings, whether that includes training, washing dishes, driving, or sleeping.
• Similarly, the ring must be comfortable to wear for long hours. During our review, the Oura Ring 3 endured around seven days on a single charge.
• When wearing the sizer rings, ensure that the sensor bumps are positioned on the palm side of your finger.
• Ideally, the rings should be worn at the base of your finger.
• If you’re stuck between two sizes, Oura suggests picking the smaller of the two rings.
• Finally, Oura warms that the plastic sizing rings may have a seam due to the mold used, which can cause discomfort for some. The actual titanium Oura Ring doesn’t have this issue.

Return to the company’s site to complete your order when you’ve found the perfect size Oura Ring. Once you’ve received the ring and find it too loose or tight, it’s not the end of the world. Oura allows users one exchange if the ring they received is the wrong size or color.

Notably, the sizing process is one of the downsides of the smart ring experience, as the fit fundamentally affects health tracking accuracy. This isn’t the case for smartwatches or fitness trackers, like the Apple Watch, where the straps can be easily adjusted. Bear this in mind if this is the first time you’re buying a smart ring.

Oura Ring size FAQs