Oura has introduced Oura Ring 5, a thinner smart ring with about 6mm width and 40% less volume than Oura Ring 4. The company says the new model is its smallest ring yet, with redesigned sensors meant to keep health tracking accurate even as the hardware gets smaller.
The search around the new Oura Ring is happening now because the design changes are not just cosmetic. Oura says it rebuilt the ring from the inside out to deliver more accurate, continuous insights in a smaller, lighter, more comfortable device, and the launch gives buyers a fresh comparison point against Oura Ring 4.
Mikko Aarras, part of the team behind the redesign, said the group explored going even smaller than about 6mm, but that the result felt too dainty. He said the company settled on a width that people found comfortable and visually appealing, a decision that shaped the rest of the engineering work.
That work shows up in the hardware. Oura Ring 5 uses precision-engineered, low-profile sensor domes designed to improve skin contact, along with more efficient LEDs and 12 stronger, more accurate signal pathways. The engineering team also rotated the LEDs 180 degrees to shorten the optical paths for red, infrared and green light, while using lower LED currents to cut power consumption.
The company says those changes let the smaller ring match or slightly improve on Oura Ring 4 performance. It points to shorter measurement paths, efficient light recycling and a larger photodiode component as part of the reason the slimmer ring can still deliver what Oura calls its most accurate generation ever made.
That is where the appeal meets the test. The new sensors are slightly larger than the ones in Oura Ring 4, pushed closer to the skin’s surface and through the metallic layer, but Oura has not released independent real-world testing showing how the new ring performs in everyday use against the older model. For now, the pitch rests on engineering claims: smaller size, more durable finish and better sensing, all in one ring.
What comes next is the part buyers will care about most — whether the promise of a smaller wearable with equal or better accuracy holds up once people wear it all day. Until there is outside verification, Oura Ring 5 remains a bold redesign with a clear upgrade story, but not yet a proven one.
