Oura Ring Gen 4: Everything You Need to Know

The Oura Ring has become synonymous with discreet health tracking, and the Gen 4 represents the biggest leap forward since the company launched its first smart ring. With continuous SpO2 monitoring, improved sleep staging powered by machine learning, a slimmer profile, and new partnerships expanding its health ecosystem, the Gen 4 makes a strong case for being the most advanced smart ring on the market. Here is everything you need to know.

Design and Comfort

The Gen 4 is noticeably slimmer than its predecessor. Oura reduced the sensor bump by roughly 25%, making the ring sit more naturally on the finger. The titanium construction remains, and the ring comes in the same Heritage (flat top) and Horizon (rounded) styles, now available in five finishes: Silver, Black, Stealth, Gold, and a new Brushed Titanium option.

Comfort has always been Oura's advantage over wrist-based wearables, and the Gen 4 continues that tradition. At between 4 and 6 grams depending on your size, you genuinely forget you are wearing it. The inner channel where the sensors sit has been redesigned with a smoother contour that reduces the slight pressure point some users noticed on the Gen 3. Oura still offers a free sizing kit, which is essential — getting the right fit affects both comfort and sensor accuracy.

Health Tracking

Sleep Analysis

Sleep tracking is where Oura has always excelled, and the Gen 4 pushes it further. The updated PPG (photoplethysmography) sensor array uses green and infrared LEDs to measure heart rate, heart rate variability (HRV), respiration rate, and blood oxygen continuously throughout the night. The new machine learning model, trained on polysomnography data, delivers more accurate sleep staging — distinguishing between light sleep, deep sleep, and REM with improved precision.

The Oura app presents your sleep data through three scores: Sleep Score (overall quality), Readiness Score (how recovered you are), and a new Sleep Efficiency metric that tracks how much of your time in bed was actually spent asleep. The algorithm also now detects mid-sleep awakenings more accurately, which was a pain point with the Gen 3.

Continuous SpO2

One of the headline additions for Gen 4 is continuous blood oxygen monitoring. The Gen 3 measured SpO2 only during sleep and only in spot-check intervals. The Gen 4 samples blood oxygen levels every 30 seconds throughout the night and offers daytime spot checks. This is particularly useful for detecting potential sleep apnea patterns and altitude acclimatisation. The data feeds directly into your Readiness Score and can trigger alerts if your SpO2 drops below a user-defined threshold.

Heart Rate and HRV

Daytime heart rate monitoring was introduced in the Gen 3 via a firmware update, and the Gen 4 improves its accuracy with a redesigned sensor layout. Heart rate variability (HRV) tracking remains best-in-class for a ring form factor, with 24/7 monitoring that captures your full autonomic nervous system profile. The app now includes HRV trend analysis over 30, 60, and 90 days, making it easier to correlate your nervous system recovery with lifestyle changes.

Temperature Tracking

Skin temperature deviation from your personal baseline is tracked continuously, and the Gen 4 improves the sensitivity of this sensor. This is particularly useful for menstrual cycle prediction (Oura's cycle tracking feature relies on temperature shifts) and early illness detection. The new Mira partnership, announced in February 2026, combines Oura's temperature data with Mira's hormone tracking to give women a more complete picture of their reproductive health.

Activity Tracking

Oura has improved activity tracking but it is still not a fitness tracker replacement. The Gen 4 uses a 3-axis accelerometer to detect steps, active calories, and workout intensity. Automatic workout detection now recognises walking, running, cycling, and strength training. However, there is no GPS and no real-time workout display on the ring itself — you will need your phone or a smartwatch for that. The Activity Score in the app balances movement, standing time, and training volume against your Readiness Score, nudging you to rest on low-readiness days.

Battery Life

Oura claims up to 8 days of battery life for the Gen 4, which is a full day more than the Gen 3 despite the addition of continuous SpO2. In practice, expect 6 to 7 days with all features enabled. Charging takes approximately 60 minutes from empty to full using the included USB-C cradle. This is still vastly better than any smartwatch — you can charge while showering and barely notice the downtime.

App and Software

The Oura app (iOS and Android) is clean and well-designed, with three main views: Readiness, Sleep, and Activity. Each presents a score out of 100 along with the contributing metrics. The Explore tab provides guided audio sessions for breathing, meditation, and sleep. Tags let you log meals, caffeine, alcohol, and other variables to correlate with your health data over time.

The $5.99 monthly subscription remains a point of debate. Without it, you get basic scores and limited history. With it, you unlock full historical data, personalised insights, detailed breakdowns, and the Explore content library. The subscription model is Oura's biggest drawback compared to buying a device that gives you everything upfront.

Who Should Upgrade from Gen 3?

If you are a current Gen 3 user, the Gen 4 is a worthwhile upgrade if: you want continuous SpO2 monitoring, the slimmer design appeals to you, or you have experienced sensor accuracy issues with the Gen 3's sleep staging. If your Gen 3 is working well and you are happy with spot-check SpO2, you can comfortably wait. Oura offers a trade-in programme that gives Gen 3 owners a discount on the Gen 4.