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Vol. IV · Issue III · 08 May 2026 N 40°42′47″ · W 74°00′21″ Cal. 2026-05-07 14:32 UTC · σ 0.61 ● Lab in session
PLATE I Territory · Smart Rings · n=10 N 40°42′ · W 74°00′ SCALE 1 : 1 device · N · NEARCTIC
Plate I · Territory

Smart Rings

10 devices researched and compared. FDA status decoded. 3-year total cost of ownership calculated. Bench instruments: Polar H10 + Kubios HRV.

Fig. I · Composite trajectory

10 devices, scored side by side

n=10 · cal. 2026-05
Composite trajectory across territories Each column shows one territory; dot height plots composite score from 1 to 10. The top filled dot is the current composite. LAT · COMPOSITE LONG · TERRITORY 10.0 8.0 6.0 4.0 2.0 7.0 RINGCONN GE… 7.5 OURA RING 4 6.8 AMAZFIT HEL… 7.5 ULTRAHUMAN … 7.8 ULTRAHUMAN … 7.0 NOISE LUNA … 7.6 CIRCULAR RI… 7.0 EVIE RING (… 5.5 COLMI R02 7.0 SAMSUNG GAL…
Each column = one device Composite 1–10 scale Score: review score when available, else category composite
Fig. II · Comparison

Price · subscription · FDA · verdict

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10 / 10 shown
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SubscriptionHRV AccuracySleep AccuracyUS Available 
RingConn Gen 2

Only mainstream smart ring with automatic sleep apnea screening, plus best-in-class battery and a charging case — at $100+ less than Oura with no subscription

$199–$299nonePENDINGPENDING◆ yes4.1 / 5·PENDINGVisit →
Oura Ring 4

Most polished app, deepest sleep/readiness science, clinically validated temperature sensing, and the strongest brand in the category

$349–$499
$5.99/mo
data lock-in
VALIDATEDVALIDATED◆ yes4.0 / 5·PENDINGVisit →
Amazfit Helio Ring

Cheapest mainstream-brand smart ring with reasonable sleep accuracy and tight integration with Amazfit smartwatches

$199.99–$299nonePENDINGPENDING◆ yes3.7 / 5·PENDINGVisit →
Ultrahuman Ring AIR

Subscription-free premium ring with the deepest circadian/metabolic angle and tight CGM integration

$314–$349nonePENDINGPENDING✕ blocked3.6 / 5·PENDINGVisit →
Ultrahuman Ring Pro

Category-leading 15-day battery, on-device ML, and subscription-free model — Ultrahuman's redesigned vehicle to legally re-enter the US after the Oura patent dispute

$100–$479nonePENDINGPENDING◆ yes3.6 / 5·PENDINGVisit →
Noise Luna Ring Gen 2

Polished Oura-alternative experience at $299 with no subscription, from India's largest smart wearable brand

$299–$299nonePENDINGPENDING✕ blocked3.5 / 5·PENDINGVisit →
Circular Ring 2

Only smart ring on the market with both on-demand ECG and FDA-cleared AFib detection, plus the widest biomarker coverage

$379–$549nonePENDINGPENDING◆ yes3.4 / 5·PENDINGVisit →
Evie Ring (Movano Health)

Only smart ring designed exclusively for women, with an open flex-fit form factor and a women's-health-first app from a US public health-tech company

$269–$269nonePENDINGPENDING◆ yes3.2 / 5·PENDINGVisit →
Colmi R02

Sub-$50 entry point that delivers the core smart ring experience and is popular with hobbyists for being hackable

$25–$50noneUNKNOWNUNKNOWN◆ yes—·PENDINGVisit →
Samsung Galaxy Ring

Deep Samsung Galaxy ecosystem integration with no subscription — leverages Samsung Health AI and seamless pairing with Galaxy Watch

$299.99–$399.99nonePENDINGPENDING◆ yes—·PENDINGVisit →
Fig. III · Buyer's guide

How to choose — by territory.

Why Smart Rings?

Smart rings are the fastest-growing wearable category in biohacking. They track sleep stages, HRV, SpO2, skin temperature, and activity — all from a device you forget you’re wearing. But the category is in flux: Oura’s patent enforcement has banned or restricted multiple competitors from the US market, subscription models vary wildly, and “FDA-cleared” claims are almost universally misleading.

What We Test

Every smart ring in our comparison is evaluated on:

  • HRV accuracy — validated against Polar H10 chest strap + Kubios HRV analysis (Bland-Altman methodology)
  • Sleep stage accuracy — compared against self-reported sleep logs and cross-referenced with published clinical validation studies
  • 3-year Total Cost of Ownership — hardware + subscription + replacement (battery degradation, finish wear)
  • US availability — live tracker of Oura patent litigation status for every competitor
  • Subscription lock-in — what data you lose if you cancel, and whether historical data remains accessible

Key Findings (2026)

  1. Oura Ring 4 remains the most polished option but the mandatory $5.99/mo subscription adds $216 over 3 years. RingConn Gen 2 and Samsung Galaxy Ring offer comparable tracking with no recurring cost.

  2. The Oura patent war has reshaped the US market. Ultrahuman Ring AIR is banned from US import; their Ring Pro is the redesigned US re-entry (May 2026). Noise Luna Ring Gen 2 is also blocked. RingConn settled via royalty agreement and remains available.

  3. No smart ring is FDA-cleared as a medical device. Natural Cycles (used via Oura’s temperature data) has FDA clearance for contraception, but that’s the app — not the ring itself.

  4. Subscription-free rings are closing the gap. RingConn, Samsung, Ultrahuman (outside US), Amazfit, and Colmi all ship without recurring fees. The data you generate stays yours.

Who Should Read This

  • Biohackers optimizing sleep and recovery
  • Athletes tracking HRV trends
  • Anyone frustrated by wearable subscription creep
  • Buyers unsure which rings are actually legal to buy in the US right now
Fig. IV · Questions

Frequently asked.

Are smart rings worth it?

Smart rings are worth it if you want continuous sleep, HRV, and recovery tracking from a device you barely notice wearing. Accuracy on sleep stages and HRV is comparable to wrist wearables for most users, and the form factor outlasts watches you forget to charge. The catch is subscription lock-in — Oura adds about $216 over 3 years; RingConn, Samsung, and Ultrahuman do not.

Which smart ring is most accurate?

For HRV and sleep, Oura Ring 4 has the largest published validation footprint and the most consistent app inference, but RingConn Gen 2 and Samsung Galaxy Ring close the gap on raw sensor data. We validate HRV against a Polar H10 chest strap with Kubios HRV using Bland–Altman analysis. Until our published lab data ships, treat marketing accuracy claims as unverified.

Do smart rings work without a subscription?

RingConn Gen 2, Samsung Galaxy Ring, Ultrahuman Ring AIR/Pro, Amazfit Helio Ring, and Colmi all ship without a recurring subscription — you keep full access to your data on the included app. Oura is the major exception: cancelling a $5.99 / month subscription locks you out of historical data and advanced metrics. Whoop is subscription-only by design.

Is the Oura Ring 4 worth $300?

Worth depends on whether you value app polish over recurring cost. Oura's software experience is best-in-class, and the temperature integration with Natural Cycles is unique. But the 3-year total cost of ownership is roughly $516 (hardware + subscription) versus about $300 for RingConn Gen 2, which delivers comparable HRV and sleep tracking with no recurring fee.

Are smart rings FDA cleared?

No smart ring is FDA-cleared as a medical device. They market under FDA's "general wellness" policy, which permits non-disease wellness claims without a 510(k). Natural Cycles, the contraception app that integrates Oura's temperature data, is FDA-cleared (510(k) K183754) — but the clearance covers the app, not the ring itself.

Fig. V · Margin notes

How we scored smart rings.

§ 1

How we compare

Instruments for this territory: Polar H10 + Kubios HRV.

Read methodology →
§ 2

Lab measurements

Raw values from our calibrated-instrument testing — irradiance, EMF, HR accuracy — with photos and timestamps.

See lab tests →
§ 3

FDA database

Verified 510(k), PMA, and registration filings — sourced from openFDA, linked to accessdata.fda.gov.

Browse filings →
Adjacent territories

Readers comparing smart rings also chart:

HRV & Recovery Wearables HRV → Biological Age Testing Bio Age →