Comparison · Fitness rings · Desk research
Circular Ring 2 vs Oura Ring 5
Side-by-side manufacturer cells from the two named ring pages. Not a lab test. Brand grouping uses the published brand field (Circular / Oura).
Quick Answer
Circular Ring 2 vs Oura Ring 5 (2026-09-19): Circular shop $299 / $349, no mandatory subscription for core features (coins unlock some premium screens). Oura is membership software at From $399 US (Silver/Black) / $499 premium finishes on ouraring.com/store, 2026-09-19. Circular cells: 7.8 × 2.55 mm, 3 g (same page also says “four grams”), sizes 6–14, ECG + cuff-calibrated BP *trends*. Quote both weight lines. Not a diagnostic device and not a lab test.
The verdict
Oura Ring 5 if you will pay that membership; Circular Ring 2 if you want the dated no-mandatory / ecosystem software sentence
Why: Subscription fork from OEM cells: Oura Ring 5 is membership; Circular Ring 2 is mixed. Quote the cells. Do not invent a software-quality winner. Circular BP is a wellness trend with monthly cuff calibration on the shop FAQ — not a cuff replacement.
Buy Circular Ring 2 if
Buyers who want a single-lead ECG on a ring and will treat it as wellness, not diagnosis.
Buy Oura Ring 5 if
Sleep- and recovery-first buyers who will pay Oura Membership and want the smallest current Oura.
Specs side by side
Same rows as the two named ring pages. Values are copied from those pages — if a cell is unpublished or contradictory on the manufacturer page, it already says so.
| Attribute | Circular Ring 2 | Oura Ring 5 |
|---|---|---|
| Materials | High-grade titanium with coating; non-allergenic clinical-grade biocompatible inner epoxy (guide)Circular Ring 2 user guide | Full titanium exterior and interior; superhard PVD on all finishes; non-allergenic BPA-free titanium inner shellOura Ring 5 support (Discover Oura Ring 5) |
| Width | 7.8 mmShop “by the numbers”; user guide dimensions | 6.09 mmOura Ring 5 support compare table; Introducing Ring 5 blog |
| Thickness | 2.55 mmShop; user guide | 2.28 mm; sensor dome height 0.7 mmOura Ring 5 support compare table |
| Weight | 3 g (shop also uses “four grams” in one marketing line — we use the 3 g spec block)Shop spec block; user guide | From 2 grams (depending on ring size)ouraring.com/store/rings/oura-ring-5 |
| Sizes | US 6–14 (nine sizes)Shop; user guide | 6–13 (generation-specific sizing kit)Oura Ring 5 supportOura says Ring 5 sizing is slightly different from Ring 4. |
| Finishes | Silver, Obsidian, Gold, Rose Gold (shop). Sensors/battery identical across finishes.shop.circular.xyz/products/circular-ring-2 | Black, Silver, Stealth, Brushed Silver, Gold, Deep RoseOura Ring 5 support; store |
| Battery (OEM) | Shop spec: 8 days power mode, ~5 days performance. Shop FAQ (2026-09-19 evening): around eight days power / four to five performance. User guide: up to 7 days (power mode); 14.5–21.5 mAh Li-Ion.Circular shop spec + FAQ; user guideDo not average 8 and 7, or 5 and 4–5. Quote the page you are citing. | Typically 6–9 daysOura Ring 5 support; store product pageOura: results vary by size, settings, activity, and battery age. |
| Charging (OEM) | Shop: 30 minutes to full. User guide: up to 60 minutes from empty; 5 V; first-use calibration ≥45 minutes at 100%.Shop; user guide §07 | About 80 minutes depending on battery level; size-specific standard charger + USB-C in the boxOura Ring 5 support; store “in the box” |
| Charging case (OEM) | Wireless charging case included; 700 mAh pack in the guide; size-specific; extra Case 2 sold for $39 on the shop. Charger is not waterproof.Shop; user guide | Every Oura set includes a size-specific charging dock + USB cable (power adapter not included). Optional Ring 5 Charging Case sold separately; Oura claims up to one month of battery and a full day of life in about 10 minutesGeneral FAQs 2026-09-18; Introducing Oura Ring 5 blog; store product page |
| Water resistance | Not publishedUser guide — Waterproof / spec; shop FAQ | 100 m / 328 ft, IP68. Ring 5 support: sauna and water sports, not diving. General FAQs (updated 2026-09-18): showering, swimming, recreational diving/snorkeling OK; not scuba; do not keep submerged over 12 hours.Oura Ring 5 support; General FAQs 2026-09-18Cite the page. Do not flatten support “not diving” and FAQ “recreational diving” into one invented rule. |
| Sensors | Single-lead ECG; 3-axis accelerometer; digital temperature; 3-LED oximeter (IR, red, green)User guide — Ring Sensors; shop | 2× triple LEDs (red, green, IR); 2× photodetectors; digital temperature; accelerometer. Blog also cites 12 signal pathways.Oura Ring 5 support; Introducing Ring 5 blog |
| Sleep tracking | Four-stage sleep, breathing rate, blood oxygen, morning score (shop). Up to 7 days flash memory depending on use (guide).Shop; user guide | Detailed sleep analysis with membership; Blood Oxygen Sensing (SpO2) listedOura Ring 5 support; store footnotesOura’s 95% sleep-staging accuracy line is an OEM validation claim vs PSG — not our lab. |
| Activity / fitness | Activity and energy; live HR / SpO2 / temperature on demand (shop). Tight-grip sports can impair PPG (guide).Shop; user guide accuracy notes | 24/7 heart rate (daytime, nighttime, activity); dynamic activity goals; Automatic Activity Detection (store: 40+ activities)Oura Ring 5 support; store |
| App | Circular app (iOS App Store, Google Play). Pair as “Gen 2” in the guide’s setup copy.User guide | Oura App (iOS / Android); 100+ integrations listed on the store pageouraring.com/store/rings/oura-ring-5; Set up the Oura App |
| Subscription / data access | No mandatory subscription for core features (shop FAQ). Some advanced screens are premium and can be unlocked with coins earned by wearing the ring.Shop FAQ | Oura Membership required for full app function. US $5.99/mo or $69.99/year; 1 complimentary month for new members. Account-tied, not ring-tied.Oura Membership support (updated 2026-09-08); ouraring.com/membershipWithout membership: three daily scores (Readiness, Activity, Sleep), battery, profile, settings, Explore. |
| Phone platforms | iPhone (App Store) and Android (Google Play). Exact OS version floors not published on the fetched guide/shop pages.User guide; shop | iOS 16+ or Android 11+ with Google Play services; device must support Bluetooth 5.0Oura General FAQs / Set up the Oura App |
| Wireless | Bluetooth Low Energy 4.2 to 5.0 (guide); airplane mode listed on the shop spec blockUser guide; shop | Bluetooth 5.0 / Bluetooth Low Energy; EMF-safe; Airplane Mode; FCC certifiedOura Ring 5 support; store |
| On-ring storage | Flash ROM up to 7 days depending on type and frequency of useUser guide | Up to three days of data storageOura Ring 5 support compare table |
| US price (dated) | $299 sale / $349 list on shop.circular.xyz, 2026-09-19Circular Ring 2 shop | From $399 (Silver, Black); $499 Gold, Deep Rose, Stealth, Brushed Silver — ouraring.com/store on 2026-09-19ouraring.com/storeGeo storefronts may show euros. Re-check the US shop on quote day. |
| Price band | Mid, no mandatory data subscriptionDerived from dated shop | Flagship membership ring ($399–$499 hardware + ongoing membership)Derived from dated US store + membership page |
| Announced | Current Circular shop SKU as of 2026-09-19 (no Ring 3 retail spec page)shop.circular.xyz | 28 May 2026ouraring.com/blog/introducing-oura-ring-5/ |
| Availability | Shop live with worldwide shipping copy and US HSA/FSA note (accessed 2026-09-19)Circular shop | Current US SKU on ouraring.com/store (accessed 2026-09-19)Oura store |
Circular Ring 2 hub notes
- Single-lead ECG (~40 s) with PDF export; guide says wellness / not a medical device.
- No mandatory subscription for core features; shop says some advanced screens use earned coins rather than cash.
- Shop vs guide battery split is documented instead of averaged (8 vs 7 days; 30 vs 60 minute charge).
Ring 2 is the ECG-forward no-mandatory-sub ring: $299 sale / $349 list, 7.8 × 2.55 mm, 3 g, sizes 6–14, 50 m / 30 min in the guide. Buy it if you want on-demand ECG and will accept Circular’s wellness wording. Skip it if you need 100 m, a 10–14 day table, or a diagnostic ECG/BP device.
Oura Ring 5 hub notes
- Smallest current Oura: 6.09 mm wide, 2.28 mm thick, 40% less volume than Ring 4 (Oura).
- Typically 6–9 days and ~80 minute charge despite the smaller shell.
- Same membership feature list as Ring 4 (sleep, 24/7 HR, Stress, Heart Health, Women's Health, SpO2). Health Radar / Counsel Health / GLP-1 Insights are described as Gen3-and-newer software, not Ring-5-only scores.
Ring 5 is the smallest current Oura: 6.09 × 2.28 mm titanium, sizes 6–13, typically 6–9 days, same membership software family as Ring 4. Buy it if you fit 6–13 and will pay membership. Skip it if you need sizes 4–5 or 14–15 (still a Ring 4 run) or you refuse a subscription.
Sources
Union of the two hub source lists. Re-open the OEM URL, not this comparison, to refresh a cell.
- Circular shop — Ring 2 — accessed 2026-09-19
- Circular — Ring 2 user guide — accessed 2026-09-19
- Oura — Introducing Oura Ring 5 — accessed 2026-09-19
- Oura Member Care — Discover Oura Ring 5 — accessed 2026-09-19
- Oura store — Ring 5 product page — accessed 2026-09-19
- Oura store — rings and accessories — accessed 2026-09-19
- Oura Member Care — Oura Membership — accessed 2026-09-19
- Oura — Membership marketing page — accessed 2026-09-19
- Oura Member Care — General FAQs — accessed 2026-09-19
- Oura Member Care — Product Safety & Use — accessed 2026-09-19
- Oura Member Care — Device Firmware Versions — accessed 2026-09-19
Frequently asked questions
Does Circular Ring 2 replace a blood-pressure cuff?
No. The shop FAQ calls blood pressure a wellness trend that asks for monthly calibration against an ordinary cuff. Not a diagnosis.
Hub A: Circular Ring 2. Hub B: Oura Ring 5.