The Oura Ring 5 comes in whole sizes from 6 to 13, and Oura says its sizes differ slightly from standard US ring sizes. That leaves the Oura Ring 5 sizing kit, a box of white plastic sizers, as the one reliable way to choose. Trying them on takes a few minutes, and Oura then asks you to wear your best fit for a full day and a night before you confirm the size. Oura allows one return or exchange per ring, so a wrong guess uses up the only exchange you get. Oura’s help center warns against the obvious shortcut, which is ordering the size you already wear in a wedding band or a Ring 4.
Before you start
- The Oura Ring 5 sizing kit. The box is labeled with the generation it was made for.
- The email address on the order, if the ring comes from Oura’s online store. For a gift, it is the address the buyer typed into the “Recipient Email” field.
- A day and a night in which you can keep a plastic sizer on, sleep included.
On Oura’s online store the kit comes free with a ring ordered with the “Size Later” option, and the store does not sell it alone. Retailers that sell kits separately give you a credit toward an Oura Ring bought from them. Oura does not want the kit back.
Use the kit made for the Ring 5
Oura rebuilt the inside of the band for the Ring 5, and its sizing page says the redesigned interior fits differently than the Ring 4. A Ring 4 size is no guide to the Ring 5 size. Oura also asks you not to size from any other ring, since other rings likely use different measurements.
The two kits look alike, with white sizers in both. The Ring 5 kit runs from 6 to 13 and the Ring 4 kit from 4 to 15, so a borrowed kit from a friend who owns a Ring 4 gives you a Ring 4 size. Each Ring 5 sizer has the same width and circumference as the finished ring. The titanium ring weighs slightly more, and Oura says the plastic does not reproduce its feel.
Find your size with the sizers
Start with the size you think is right and work up or down from it.
- Pick the finger. Oura recommends the index finger for the best accuracy, and the middle or ring finger also works well. Avoid a finger whose knuckle is much wider than its base, so the ring can sit securely.
- Turn the sizer so the sensor bumps inside it sit on the palm side of the finger. With a Ring 4 kit, Oura says to wear the sizer with the size number visible on top of the hand instead.
- Slide it down to the base of the finger. It should feel snug, not tight.
- Make a fist. If you see a gap between the sizer and the top of your finger, try the next size down.
- Swap hands. Try the sizer on your other hand and on a second finger. A ring that fits snugly on more than one finger can move to another one if your fingers change later.
- Wear the best fit for at least 24 hours, including a night’s sleep.
Fingers change size through the day and the night, which is why Oura asks for a whole day. Check the sizer again when you wake up and after a workout or a long day at a keyboard. If it still passes the fist test and still feels comfortable, that is your size.
When two sizes both fit
Take the smaller one. Oura gives three reasons. The sensors work best in close contact with the skin, especially on the underside of the finger. A snug fit keeps the readings consistent from one night to the next. And the plastic sizers can feel a bit “stickier” on the skin than titanium, so the finished ring may slide on more smoothly than the sizer did.
The kit has no size below 6 or above 13. If the 6 is loose on every finger you would wear it on, or the 13 is tight on all of them, the Ring 5 has no size for you. Oura still sizes the Ring 4 from 4 to 15 with its own kit, though some Ring 4 rings have the battery faults Oura disclosed in its IPO filing.
Confirm the size where you bought the ring
Oura ships nothing until the size is confirmed, and where you confirm it depends on where the order came from:
- Oura’s online store: in “My Orders”, using the steps below.
- A kit bought from a retailer: go back to the same retailer and buy the ring in your size.
- An employer program: on Oura’s business site.
- Essence Healthcare: scan the QR code on the back of the sizing kit.
For an order from Oura’s online store:
- Open “My Orders” on Oura’s website and enter the email address used for the order.
- Click “Get code”.
- Find the sign-on code in your inbox. It works once and expires after 15 minutes.
- Open the order and confirm the ring size. If the order holds more than one ring, give each one a size, or the order will not ship.
Oura’s shipping email usually follows within one to two days, and the ring should arrive two to five business days after it. To change the size before the ring ships, Oura’s answer is to cancel and order again. Oura cancels an order until it has been prepared for shipping: use the cancel option in My Orders, or Oura’s support chat if that option has gone. Once the ring has shipped, a different size means an exchange after it arrives.
If the ring does not fit when it arrives
Repeat the fist test with the real ring on, and give it a full day before deciding. If it is still loose or tight, the fix depends on where you bought it.
Rings from Oura’s online store can be returned or exchanged within 30 days of delivery, and Oura allows only one of the two per ring. An exchange only swaps the size of the same ring. A different color or model means returning the ring for a refund and placing a new order, and once an exchange is complete, a refund is no longer possible. In the US you start either one in Oura’s self-service portal, where an order appears three days after it ships. You need the order number, which begins with “SO-“, and the order email. The portal issues a prepaid label, the package has to go out within 14 calendar days, and it should hold everything that came in the box.
Rings bought from a retailer go back under that retailer’s policy, which Oura says may differ from its own. Whatever the route, Oura’s sizing page asks anyone whose ring still feels too tight or too loose after using the sizer to contact its Member Care team. If you cannot remove the ring yourself, Oura’s Ring 5 booklet says to seek immediate medical attention.
Check the size on the ring itself
The size is marked inside the band, on the side opposite the sensors. The Oura App shows it too: tap the icon in the upper-right corner of the “Today” tab to open “My Devices”, then tap your ring. If the number differs from the one you confirmed, contact Oura before the 30 days run out.
Oura’s Ring 5 booklet says to wear the ring with the dimple facing the palm. In its drawing, the dimple is a small oval on the outside of the band.
The charger in the box is made for one ring size. So is the Ring 5 charging case, sold separately: retailers list it by size from 6 to 13 and say it fits only a Ring 5 of the same size. Buy one after the ring has passed the fist test through its first weeks, while the 30-day window is still open.
