Oura has confirmed that some Oura Ring 4 rings have a battery fault, and the admission is in a prospectus written for investors. The filing, first lodged with the US Securities and Exchange Commission on 3 September and amended on 21 September ahead of a Nasdaq listing under the ticker OURA, says “certain cohorts of Oura Ring 4 have exhibited battery performance issues”. Oura adds that it has replaced affected rings free of charge “and, in some cases, outside of the warranty period.” That last clause is the one to remember if your Ring 4 battery no longer lasts the week.
What the filing says about the batteries
The wording is brief. Oura does not name the batches, the months they were built, the symptom or the number of rings involved. A cohort here means a group of rings made in the same period, so two Ring 4s bought from the same shop can behave differently.
The problem comes up in three places. Besides the risk section quoted above, the explanation of costs puts an $84.4 million rise in warranty expense in the year to 30 September 2025 down to reserves for those same Ring 4 batteries. And the same cause is named again for lower margins in the nine months to 30 June 2026, alongside a line about the AI diagnostic tools Oura now uses to process these claims.
The word the filing uses is performance. Nothing in it describes overheating or swelling, and it mentions no recall.
Oura’s support pages say something else
Three Oura help documents, all revised in the past six weeks, carry no trace of it. Updated on 18 August, the warranty FAQ lists “consumable parts, including batteries” among the things the limited warranty does not cover. The Oura Ring 4 battery life article was updated on 21 September, the day of the amended filing, and still ends by saying that “based on early usage of Oura Ring 4, these controlled environment estimates remain accurate.” The Known Issues list, revised on 28 September, has entries for missing sleep data and slow syncing and none for the battery.
An owner reading the help site would conclude that a fading battery is normal wear. An investor reading the prospectus learns that some of it is a fault Oura pays to fix.
Both can be true for different rings, since every lithium cell does lose capacity. That is why the useful question is how far your ring has drifted from the rated figure.
The warranty bill, divided by rings sold
Each time Oura sells a ring, it sets money aside for the warranty claims it expects. The prospectus gives that provision and the number of rings sold, so the two can be divided.
| Period | Warranty provision | Rings sold | Set aside per ring |
|---|---|---|---|
| Year to 30 Sep 2024 | $12.6 million | 1.0 million | about $13 |
| Year to 30 Sep 2025 | $103.3 million | 2.3 million | about $45 |
| Nine months to 30 Jun 2026 | $113.2 million | 3.1 million | about $37 |
The division is ours and it is rough. Oura counts rings sold after returns and warranty replacements, and the provision covers every model and every kind of defect. Still, the Ring 4 went on sale on 15 October 2024, two weeks into the year in which the amount per ring more than tripled.
Claims Oura actually paid grew from $9.7 million to $28.8 million in that year, then reached $75.5 million in the following nine months. On 30 June Oura still held $132.3 million for claims it expects but has not yet paid, the largest balance anywhere in the filing.
Is your ring one of them?
The Ring 4 is rated at five to eight days on a charge. That comes from new rings in sizes 8 to 10, with blood oxygen sensing off, eight hours of sleep a night and an hour of detected activity a day. According to the same help page, blood oxygen sensing can take up to two days off, and two or three hours of daily activity tracking up to two more. Smaller rings hold smaller batteries.
So a small ring with every sensor on can land near three days and still sit inside Oura’s own description. Start there. Switch blood oxygen sensing off for a few nights, update the app and the ring firmware, charge to full and note how long it lasts.
If the ring still falls well short of five days with those settings, it is behaving worse than Oura promises for a new Ring 4. That is the case to take to support. Oura has not published the threshold it uses to call a battery faulty, and a ring from late 2024 will have lost some capacity through ordinary use.
Asking Oura for a replacement
Claims start with Finn, the virtual assistant in the app and on the support site. It can approve some replacements on its own and hands the rest to a person by chat or email. The warranty page asks for your order number, a description of the problem and what you have tried, photos or screenshots, and the ring’s model and size from the My Devices page in the app.
Screenshots of the battery level on several consecutive days make the strongest case. If your ring is past its first year, say so, and quote Oura’s statement to investors that it has replaced affected Ring 4s outside the warranty period. The filing does not promise that to everyone, and Oura has not said how it decides.
Outside the US, check the legal minimum before accepting “out of warranty” as an answer. Across the EU the seller is liable for faults for at least two years, and Oura’s own warranty page says its team applies whatever coverage your country requires.
Before you send anything, sync the ring. Only data already synced to your account carries over, and the old ring may be disabled once a replacement is approved. The new one will be the same model and size, possibly a refurbished ring, covered for the rest of your original warranty or 90 days, whichever is longer. Don’t sell or give away the ring it replaced: the warranty page asks owners to recycle it.
Buying a ring this autumn
The Ring 5 arrived on 4 June 2026 with a rating of six to nine days, and the filing says only that Oura is monitoring its performance closely. Like the Ring 4, it has a sealed battery that cannot be replaced, which the Oura Ring 5 review weighs against the price and the membership. Whichever model you choose, keep the receipt and the purchase date where you can find them in two years.
The advice changes if Oura lists the affected batches or adds the battery to its Known Issues page. Until then, the prospectus is the only place Oura has said it.
