Oura Ring 4 vs Ultrahuman Ring Air — Smart Rings Go Mainstream

Smart rings have quietly moved from niche gadgets to serious contenders in wearable health tech. The appeal is obvious: they’re less obtrusive, more comfortable at night, and built for constant use.

In 2025, two rings are creating buzz: Oura Ring 4, the latest from a veteran in the space, and Ultrahuman Ring AIR, the upstart that’s making waves especially in India and among biohacking circles. Let’s dig into both — what they do well, their tradeoffs, and which ring might be right for you.

Design & Build

Oura Ring 4

• Material & Form: Made from titanium, fully non-allergenic, with recessed sensors (no bumps inside) for a smooth fit.
• Size Specs: Width ~7.9 mm, thickness ~2.88 mm. Weight varies by size — around 3.3 to 5.2 grams.
• Durability & Water Resistance: Rated for water resistance up to 100 m / 328 ft, which lets you wear it in showers, pools, or even saunas (within limits).

Oura’s design has been refined to reduce bulk and improve comfort, especially for overnight wear. Health+2WIRED+2

Ultrahuman Ring AIR

• Material & Form: Built with a titanium frame reinforced with a tungsten carbide / carbon coating in some versions. ultrahuman.com+3Sypnotix+3Medium+3
• Size Specs: Thickness ~2.45 mm, width ~8.1 mm; weighs around 2.4 grams (though heavier versions vary by size) Computech Store+3Sypnotix+3Croma+3
• Water Resistance: Ultrahuman states water resistance (often up to 100 meters in spec listings) Computech Store+2Croma+2

Ultrahuman bets on extreme comfort and lightness as key differentiators: the ring is often marketed as among the lightest smart rings.

Sensors & Metrics

Here’s what each ring tracks and how they interpret data:

Oura Ring 4

• Sensors: Red & infrared LEDs (for SpO₂, respiration), green/IR (for heart rate, HRV), accelerometer, temperature sensors.
• Metrics / Features:
  • Resting heart rate & HRV
  • SpO₂ (blood oxygen)
  • Skin temperature deviations / trend
  • Sleep staging & readiness scores
  • Activity & movement tracking
  • Respiratory rate
  • Optional / paid features: deeper health insights via Oura Labs features, tagging timelines, etc.

Oura has refined its algorithm and UI, focusing heavily on sleep & recovery as its prime use case.

Ultrahuman Ring AIR

• Sensors: Likely PPG (optical), temperature sensor, 6-axis motion sensors, SpO₂, etc.
• Metrics / Features:
  • Heart rate & HRV
  • SpO₂ / oxygen saturation
  • Sleep & recovery trends
  • Movement / activity data
  • Skin temperature / deviations
  • “Personal Best” badges / milestones in app Ultrahuman+1

Ultrahuman’s marketing emphasizes real-time insights, recovery scores, and biofeedback nudges.

Battery & Charging

Oura Ring 4

• Battery Life: Up to 8 days (typical use) is often quoted in reviews.
• Charging: Comes with new charging dock (non-compatible with Gen3) — Oura says the new dock covers the ring to protect it, and charges faster.

Some reviewers have reported 4–7 days in more aggressive usage scenarios.

Ultrahuman Ring AIR

• Battery Capacity / Life: Uses a ~24 mAh battery. In tests, battery life is around 4–6 days depending on usage.
• Charging Time: ~1.5 to ~2 hours to full charge (wireless).

In real usage, 4 days before dropping under 20% is commonly reported.

App & Ecosystem / Software

Oura

• Strong, mature app ecosystem with History, Vitals, Timeline features.
• Advanced features like Tags, meal journaling, future predictive tools (in Oura Labs).
• Subscription model for advanced insights (some features behind paywall).
• Solid cross-platform support (iOS & Android).

Ultrahuman

• Offers full access to most metrics without a subscription (one-time purchase).
• App includes Personal Best badges, shareable insights, and social / milestone features.
• Strong focus on real-time feedback, nudges, recovery coaching rather than just retrospective stats.
• local support and community presence, especially in Indian / Asian markets via Ultrahuman’s health tech brand.

Performance & Real-World Use

Accuracy & Consistency

• Early reports and reviews say Oura 4’s improved sensors and recessed design deliver better consistency in HR, HRV, and SpO₂ readings than past models.
• Ultrahuman also gets praise for accuracy and light weight, though battery and software stability sometimes draw criticism.
• Some user reports suggest battery & software glitches (Ultrahuman) — e.g. “software works one week then off,” or scratches on titanium versions.

Comfort & Wearability

• Oura’s recessed sensor design feels flatter on finger, making it more comfortable during sleep or finger movement. WIRED+1
• Ultrahuman’s ultra-light design is a big plus for users who dislike bulk. ultrahuman.com+3ultrahuman.com+3Croma+3
• Fit / sizing matters. Some users report certain sizes are a bit loose in finger movement. Reddit

Ecosystem, Market Position & Trends

• Oura, being an older player, has a more mature product ecosystem, deeper data features, a reputation for reliability, and a large user base.
• Ultrahuman is positioning itself strongly in the Indian / Asian markets, with emphasis on affordability, no-subscription model, and health-tech integration in that region.
• In a notable development, Ultrahuman may face legal/market constraints: Oura reportedly won patent enforcement over Ultrahuman and Ringconn, which could impact their operations. (As of recent news, Ultrahuman and Ringconn were ordered to cease sales after October 21, though support promised for existing users) WIRED
• Oura has expanded its 4 lineup by introducing ceramic versions and a portable charger case, and now supports multi-ring use in its app.

Which One Should You Choose?

Here’s a quick guide based on user profiles:

Conclusion

The Oura Ring 4 vs Ultrahuman Ring AIR matchup shows how far smart rings have come — they’re no longer niche novelties but serious tools for health & lifestyle tracking.

Oura offers a more polished, mature package with depth in data, a strong ecosystem, and a track record. Ultrahuman brings lightness, affordability, and bold health coaching features — especially appealing in markets like India.