Smart rings offer the most comfortable way to track HRV overnight. Oura Ring 4 brings improved accuracy with all-titanium design; Ultrahuman offers no subscription fees.
Comparison Overview
| Category | Oura Ring 4 | Ultrahuman Ring Air |
|---|---|---|
| Price Model | $350-500 + $6/month optional | $349 one-time ✓ |
| Ultrahuman has no ongoing fees | ||
| Sleep Tracking | Excellent, years of refinement ✓ | Very good, improving rapidly |
| Oura has more mature algorithms | ||
| HRV Accuracy | Best-in-class (2025 study) ✓ | Good PPG accuracy |
| Oura Ring 4 ranked highest in accuracy study | ||
| HRV Analysis | Readiness Score with contributors ✓ | Movement Index with HRV data |
| Oura's insights are more detailed | ||
| Design | All-titanium, concave inner ✓ | Titanium with resin inner |
| Oura Ring 4's design improves sensor contact | ||
| Additional Sensors | SpO2, temperature, HR | SpO2, temperature, HR + CGM option ✓ |
| Ultrahuman offers metabolic integration | ||
| Battery Life | 7-8 days ✓ | 4-6 days |
| Oura Ring 4 improved significantly | ||
| Research Validation | Multiple peer-reviewed studies ✓ | Limited published research |
| Oura has more scientific validation | ||
The Bottom Line
Choose Oura Ring 4 for best-in-class accuracy, mature smart ring experience, and proven algorithms. Choose Ultrahuman Ring Air if you want to avoid subscription fees, are interested in metabolic tracking (CGM integration), or want a capable alternative at lower total cost.
Detailed Reviews
Oura Ring 4
Best for those who prioritize comfort and discretion. The ring form factor is ideal for sleep tracking, though the...
Full reviewUltrahuman Ring Air
A solid Oura alternative with no subscription fees. Strong HRV and sleep tracking in a comfortable form factor. Best...
Full review