The world’s smallest smart ring, Oura Ring 5 offers powerful health sensing in an ultra-compact, jewelry-like design. With 40% less volume and a more durable finish than Oura Ring 4, Oura Ring 5 sets a new standard for wearable technology.
“We rebuilt Oura Ring from the inside out to deliver more accurate, continuous insights in a smaller, lighter, more comfortable ring—so people can focus on living their lives, not tracking them,” says Tom Hale, Chief Executive Officer at Oura.
To explore the craftsmanship behind this milestone, we sat down with our industrial design and optical sensing teams to discuss how they created this remarkable new version of Oura Ring.
Re-Engineering Oura Ring from the Ground Up
The primary goal in developing Oura Ring 5 was to create the smallest possible smart ring in the “perfect size that people find comfortable and visually appealing,” says Mikko Aarras, Staff Industrial Designer at Oura.
Based on research across a broad range of people, the team found that the current width of Oura Ring 5—about 6mm—was the most preferred for style and comfort. This size also worked best for a wide range of activities. Aarras notes that his team explored going even smaller, but that was found to feel too “dainty.”
Once the ideal size was determined, the process became one of working backward to fit the battery and design architecture into that specific footprint.
When work began, the team quickly realized that designing a product this small creates a “domino effect,” where changing one element necessitates changes in everything else, Aarras explains. “This made the project exceptionally challenging for industrial design, mechanics, and electronics.”
Rethinking the ring’s sensing architecture, the team optimized every component for stronger signals and greater accuracy. The redesigned system features precision-engineered, low-profile sensor domes that improve skin contact, more efficient LEDs, and 12 stronger, more accurate signal pathways. Together, these new sensor optical design details deliver more accurate metrics on key features and high fidelity signals.
Smaller & More Accurate Than Ever
Because Oura Ring 5 has fewer optical paths available due to its small size, the engineering team relied on improving the basic function of the existing signal pathways. This included changing and rotating the LEDs 180 degrees to shorten overall optical paths for red, infrared, and green light.
“The reduced size of Oura Ring 5 led to a sensor with shorter light paths,” says J-T Mäkinen, Principal System Engineer at Oura. “The design balances signal strength and quality with the ability to drive LED chips with lower currents, meaning less power consumption.”
Compared to Oura Ring 4, Oura Ring 5 achieves parity with or slight improvement over performance by utilizing shorter measurement paths, incorporating efficient light recycling, and using a larger photodiode (PD) component. The result: Oura Ring 5 is our most accurate generation ever made.
On the inside of Oura Ring 5, the redesigned sensors containing the LEDs and PDs, are slightly larger than those in Oura Ring 4. The reason: “Because the ring is so thin, the engineering team had to push the LEDs and PDs closer to the skin’s surface and through the metallic layer,” explains Mäkinen.
Thanks to an innovative flat-top design, the sensors inside Oura Ring 5 are extremely comfortable and subtle for a smooth fit and feel—even though they are slightly higher than the sensing domes in Oura Ring 4 (0.7 mm vs. 0.3 mm).
The Subtle Power of Oura Ring 5
The Improvements: More powerful LEDs for clearer, more consistent readings Optimized positioning puts the sensor closer to your skin for better signal detection 12 optimal signal pathways ensure greater accuracy across a variety of fingers and skin tones The Results: Oura Ring 5 is the most accurate Oura Ring yet, with: 12% more accurate overnight HRV than Oura Ring 4 for the average member 24% improvement in signal quality for workout heart rate, translating to a 19% increase in accuracy for top activities such as running, cycling, and walking. |
A Finish Built to Last
Our most resilient generation yet, Oura Ring 5 is designed specifically for the rigors of Oura Members’ daily activities—workouts, commutes, cooking, sleeping, and more.
At the core of Oura Ring 5 is a high-grade titanium construction. This material was chosen not only for its exceptional strength-to-weight ratio, but also for its non-allergenic properties, ensuring comfort and skin safety for sensitive skin during long-term wear.
To maintain a sleek aesthetic, Oura Ring 5 features an extra-strong physical vapor deposition (PVD) coating process. This improved finishing technique significantly increases the ring’s scratch resistance, provides a robust shield against the abrasions of daily life, and ensures your Oura Ring retains its premium, “out-of-the-box” look for longer.
Miniaturized, Without Compromise
Oura Ring 5 stands as a testament to what happens when sophisticated engineering meets a deep understanding of human physiology. By shrinking the hardware while expanding its capabilities, Oura Ring 5 eliminates the friction between wanting to understand your body and wanting to live your life without distraction.
With increased accuracy, greater durability, and smaller size, Oura Ring 5 is strong enough for your toughest workouts, elegant enough for your most formal occasions, and precise enough to provide the clarity you need to thrive.