Oura Ring 5 Review: The Best Smart Ring Gets Much Smaller

Oura Ring 5 is roughly 40% smaller by volume than Ring 4 and redesigned its optical system with stronger LEDs and improved sensor contact. The company advertises 99% heart-rate accuracy compared with ECG and 95% sleep-staging accuracy compared with clinical sleep testing, although the sleep claim needs some context that I'll come back to below.

Oura Ring 5 Core tracking includes:

Sleep Score and sleep stages, resting and 24/7 heart rate, HRV, blood oxygen, breathing disturbances, temperature trends, Readiness, Activity, Daytime Stress, Resilience, Cardiovascular Age, Cardio Capacity and estimated VO2 max, Symptom Radar, Cycle Insights and period prediction, automatic activity detection, Blood Pressure Signals, and Oura Advisor with AI-assisted insights.

Feature availability can vary by country.

The Oura Ring 5 doesn't reinvent what Oura tracks. Instead, it fixes one of the biggest problems smart rings have always had: they still felt like pieces of technology wrapped around your finger.

At just 6.09mm wide, 2.28mm thick and starting at roughly 2g, the Ring 5 is dramatically smaller than the Ring 4. That difference matters more in everyday use than another sensor or headline feature would. Professional reviewers consistently describe it as significantly more comfortable, while owners upgrading from older Oura generations often say they simply forget they're wearing it.

Despite the smaller body, Oura hasn't sacrificed its biggest strengths. Sleep, resting heart rate, HRV, temperature, stress and recovery tracking remain excellent, while the Oura app continues to be the real reason to choose this ring. Instead of presenting pages of raw measurements, Oura turns them into useful Sleep, Readiness and Activity scores and highlights longer-term patterns that are easy to understand.

Fitness tracking has improved too. Automatic activity detection covers more than 40 activities, and steady-state heart-rate tracking can be impressively accurate. However, the Ring 5 still lacks onboard GPS and isn't a replacement for a Garmin or Apple Watch if detailed training data is your priority. Wearing a metal ring while lifting weights isn't particularly appealing either.

Battery life is rated at six to nine days depending on ring size and settings. Many reviewers and owners achieve roughly a week, although there are enough reports of three-to-four-day battery life and occasional rapid battery degradation to make this an area worth monitoring.

Oura Ring 5 Battery Degradation
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The bigger problem is cost. The Ring 5 starts at US$399, or around C$529.99 in Canada, and most of its useful insights require an ongoing Oura membership. That's increasingly difficult to ignore when the RingConn Gen 3 offers up to roughly two weeks of battery life without a subscription.

Still, competitors haven't quite caught Oura where it matters most. RingConn offers better value and Samsung has strong ecosystem integration, but Oura combines exceptional comfort, mature sleep and recovery tracking and the most polished smart-ring software into one package.

Ring 4 owners don't need to rush to upgrade unless its size bothers them. For everyone else looking for the best overall smart ring, however, the Oura Ring 5 is currently the benchmark.

The 4.5/5 feels right to me here. The hardware and software are close to 5-star territory; the subscription plus RingConn Gen 3's much stronger value proposition are what keep me from giving Oura the full 5.