Here’s How Small the Oura Ring 5 Really Is

I’ve been wearing the Oura Ring 5 for a few days now. My full review is coming soon, but so I have one major takeaway so far: The Oura Ring 5 is impressively thin, as was promised. It’s also the most comfortable smart ring I’ve ever worn. 

The Oura Ring 5 is getting closer to the size of a non-smart ring

The photo above shows the size of the Oura Ring 5 (center, in gold) next to the previous generation, the Oura Ring 4 (right, in black). To the left are two regular jewelry rings for comparison. The latter rings are chunkier than a lot of people’s delicate little wedding rings (what can I say, I’ve always appreciated a sturdy titanium ring), but they’ve always looked tiny when placed next to a smart ring. Compared to the Oura Ring 5, though, the difference is a lot less dramatic than with any other smart ring I’ve worn.

The Oura Ring 5 is definitely the smallest smart ring I’ve ever seen

Left stack, top to bottom: Samsung Galaxy Ring, Ultrahuman Ring Air, RingConn Gen 3. Right stack, top to bottom: Oura Ring 5, Oura Ring 4, Oura Ring 3.
Credit: Beth Skwarecki

Based on specs, I knew this ring would be the smallest one I’ve tried, and here’s the proof: In the photo above, the three rings on the right-hand stack are various generations of Oura rings, with the Oura Ring 5 on top. On the left stack, the rings are (top to bottom) the Samsung Galaxy Ring, the Ultrahuman Ring Air, and the RingConn Gen 3. 

RingConn Gen 3, left; Oura Ring 5, right.
Credit: Beth Skwarecki

And this photo offers a direct comparison between the Oura Ring 5 and the RingConn Gen 3, its closest competitor with regard to size. The Oura Ring 5 is in gold, the RingConn 3 in silver. 

Here’s how the Oura Ring 5 compares to previous generations of Oura Rings

Left to right: Oura rings 3, 4, and 5. Note that the gen 3 ring is a larger finger size (size 9) than the other two (both size 8).
Credit: Beth Skwarecki

In the photo above, you can see the last three generations of the Oura ring: the 3, 4, and 5, from left to right. You can see that the gen 3 had round sensor bumps on the inside, while the Oura Ring 4 flattened those out for a flush interior. The Oura Ring 5 brings back some low-profile bumps to improve skin contact. 

Is the Oura Ring 5 worth the upgrade? 

The Oura Ring 5 is definitely nicer-looking and more comfortable than the previous generations, and Oura says the finish is more scratch-resistant. Those are good reasons to go for the 5 over an earlier generation, all else being equal. That said, if you already have an Oura Ring 4, I’m less sure whether it’s worth upgrading. From generation to generation, Oura’s rings have only offered minor hardware improvements over the years. They get a little more comfortable and a little more accurate with each iteration, but I’d have a hard time telling someone they should ditch their current ring, whatever generation they have. You just don’t gain much from keeping up with the times. 

There’s a big caveat on my conclusion, though: battery longevity. My Oura rings keep dying right around the two-year mark, and from what I’ve seen from other Oura users, this seems to be a common issue. This happened with my gen 2 ring, then the gen 3 that replaced it, and the battery on my second gen 3 ring wasn’t doing well before I swapped it out for the Oura Ring 4 that I got as a review unit (I made that switch sometime last year). In recent weeks, I’ve noticed my Oura Ring 4 now only holds a charge for about three days at a time, down from about a week when it was new. 

I asked Oura if it’s doing any research on battery longevity or making the rings last longer, but the company didn’t share any specifics. I understand that it’s hard to build a long-lasting battery in such a small device, so I’m not faulting Oura for the limits of technology. But battery longevity being what it is, Oura customers need to know that these rings won’t last forever. Interestingly, the batteries’ lifespan seems to roughly coincide with the release cycle of new generations of the device. That’s perfect timing if you’re ready to upgrade, and more than disappointing if you’re not.