Oura Ring costs $349–$499 upfront for hardware you wear on your finger — membership is included free for the first year, then $5.99/mo or $69.99/yr to keep accessing your own data. Kreev works with the Apple Watch already on your wrist — no new hardware required.
Hardware + subscription, year one. No hidden fees.
Kreev: free to start, Sentinel $39.99/yr — no hardware required. Oura: Ring 4 $349–$499, membership free for year one, then $5.99/mo or $69.99/yr.
| Feature | Kreev | Oura Ring |
|---|---|---|
| Additional Hardware Cost | $0 | $349–$499 (ring required) |
| Subscription | $5.99/mo or $39.99/yr | $5.99/mo or $69.99/yr (first 12 months free) |
| Commitment | Cancel anytime | Cancel anytime |
| Works with Apple Watch | ✓ Yes | ✕ No |
| Recovery Score | ✓ | ✓ (Readiness Score) |
| Personal Baseline (Z-Score) | ✓ | ✕ Population average |
| Algorithm Transparency | Published | Black box |
| Plain-Language Insights | Daily narrative, generated on-device | Basic summaries |
| Free Tier | Yes | ✕ |
| Trial | 1-month Sentinel App Store trial | Varies |
| Data Privacy | Kreev's watch app can't even read Apple Health — your iPhone computes your scores and sends only the finished numbers to your watch, over Apple's own encrypted connection | Standard policy |
Oura requires a $349+ ring before you can access a single metric. Kreev works with the Apple Watch already on your wrist. Start for free — no upfront hardware cost.
Oura's Readiness Score benchmarks you against population data. Kreev uses Z-score statistics against your own rolling baseline — so a night of 7.8 hours is evaluated against your typical sleep, not a global average.
Oura gives you a readiness score and brief tips. Kreev generates a full plain-language narrative every morning — on your iPhone, explaining each metric's contribution to your score and how it compares to your baseline.
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