How does Oura Ring sizing work?

How the Oura sizing kit works

1. Get a kit. Choose Size Later when you buy on ouraring.com and a complimentary sizing kit comes with your order. Oura doesn't sell kits on their own in its online store; authorized retailers do, and the kit price becomes a credit toward a ring from that retailer.
2. Use the kit for your ring model. Kit boxes are labeled by generation. Oura says to use the matching kit for the most accurate fit.
3. Wear a sizer for at least 24 hours, including while you sleep, since finger size changes during the day.
4. Confirm your size. For an ouraring.com order, confirm it in My Orders. For a retailer kit, go back to the retailer and buy your size. You don't need to return the kit.

Already know your Oura size from an earlier Oura ring or a friend's kit? You can pick it at checkout. Oura says not to size from other rings you own.

Oura Ring sizes by model

• Oura sizes aren't standard ring sizes. Test with Oura sizers even if you know your usual ring size.
• The sizers match the real ring's width and circumference, but the real ring is slightly heavier.
• Need a size outside 6 to 13? Ring 4 covers more sizes. See Oura Ring 4 vs 5.

Which finger to wear an Oura Ring on

• Index finger is Oura's recommendation for the best accuracy.
• Middle or ring finger also work.
• Skip fingers where the knuckle is much wider than the base, since a ring that slips over a big knuckle can be loose at the base.
• Try both hands and several fingers. Oura's sizing blog suggests a size that fits more than one finger, so you can switch fingers later.

Wear the ring with the sensor bumps on the palm side of your finger, touching your skin. Oura's sensors work best with close skin contact, especially on the underside of the finger.

How an Oura Ring should fit

• Snug, not tight, sitting securely at the base of your finger.
• Make a fist. If a gap opens between the ring and the top of your finger, try a smaller size.
• Size with warm hands. Oura's blog says fingers are smallest when cold, so warm up first to avoid a ring that feels tight later.
• Between two sizes, choose the smaller one. Oura says the plastic sizers can feel stickier than the real ring.
• Too tight if it won't turn at the base or needs soap to come off. Too loose if it spins freely, slides off when your hand relaxes or the sensor bumps lose skin contact.

If your Oura Ring doesn't fit

• Bought on ouraring.com: Oura accepts returns and exchanges within 30 days of delivery for any reason, if the product is fully functional and undamaged. An exchange can only be for a different size of the same ring, and each item gets one return or one exchange.
• Bought from a retailer: returns and exchanges go through that retailer, under its own policy.
• Still unsure? Oura's Member Care team says to contact them if the ring feels too tight or too loose, even after using the sizer.
• Check your current size on the inside of the ring, opposite the sensors, or in the Oura app under My Devices.

If you return the ring for a refund, Oura says to cancel your membership too. For the full cost of ring and membership, see Oura Ring price. If you track sleep or HRV, Gabriel can read that data next to your lab results; ask Gabriel anything free by app, web, text or voice.