RingConn Gen 2 Size Chart & Fit Guide
An independent, comprehensive sizing reference for the RingConn Gen 2 smart ring. Compare sizes 6 through 14 in millimeters, understand how the squircle anti-rotation profile and ultra-slim 2.0 mm thickness affect fit, and learn why the official sizing kit is essential.
How Does RingConn Gen 2 Sizing Work?
RingConn Gen 2 Sizing Table
Comprehensive sizing chart mapping RingConn sizes 6–14 to inside diameter, circumference, and regional standard sizes.
| RingConn Size | US / Canada | UK / Australia | EU / ISO | Inside Diameter (mm) | Inside Circ. (mm) | Fit & Squircle Sensor Notes |
|---|---|---|---|---|---|---|
| RingConn SizeSize 6 | US / Canada6.0 | UK / AustraliaL½ | EU / ISO52.0 | Inside Diameter (mm)16.51 mm | Inside Circ. (mm)51.87 mm | Fit & Squircle Sensor NotesSmallest available RingConn size (~51.6 mm circ). Fits women’s petite ring or slender index fingers. No size 5 is manufactured. |
| RingConn SizeSize 7 | US / Canada7.0 | UK / AustraliaN½ | EU / ISO54.5 | Inside Diameter (mm)17.32 mm | Inside Circ. (mm)54.41 mm | Fit & Squircle Sensor NotesPopular women’s index or middle finger size (~54.5 mm circ). If between sizes 7 and 7.5, size up to 8. |
| RingConn SizeSize 8 | US / Canada8.0 | UK / AustraliaP½ | EU / ISO57.0 | Inside Diameter (mm)18.14 mm | Inside Circ. (mm)56.99 mm | Fit & Squircle Sensor NotesCommon crossover size for women’s index or men’s ring finger (~56.9 mm circ). Size up to 9 if you wear 8.5. |
| RingConn SizeSize 9 | US / Canada9.0 | UK / AustraliaR½ | EU / ISO59.5 | Inside Diameter (mm)18.95 mm | Inside Circ. (mm)59.53 mm | Fit & Squircle Sensor NotesStandard men’s ring-finger or women’s thumb size (~59.5 mm circ). Squircle corners must comfortably slide over knuckle. |
| RingConn SizeSize 10 | US / Canada10.0 | UK / AustraliaT½ | EU / ISO62.0 | Inside Diameter (mm)19.76 mm | Inside Circ. (mm)62.08 mm | Fit & Squircle Sensor NotesMost popular men’s index and middle finger size (~62.3 mm circ). Provides stable palm-side sensor orientation. |
| RingConn SizeSize 11 | US / Canada11.0 | UK / AustraliaV½ | EU / ISO64.5 | Inside Diameter (mm)20.57 mm | Inside Circ. (mm)64.62 mm | Fit & Squircle Sensor NotesLarger men’s index or middle finger size (~64.8 mm circ). Ensure comfortable clearance during morning finger swelling. |
| RingConn SizeSize 12 | US / Canada12.0 | UK / AustraliaX½ | EU / ISO67.0 | Inside Diameter (mm)21.39 mm | Inside Circ. (mm)67.20 mm | Fit & Squircle Sensor NotesMen’s extra-large size (~67.0 mm circ). Slim 2.0 mm thickness ensures comfortable adjacent-finger spacing. |
| RingConn SizeSize 13 | US / Canada13.0 | UK / AustraliaZ½ | EU / ISO69.5 | Inside Diameter (mm)22.20 mm | Inside Circ. (mm)69.74 mm | Fit & Squircle Sensor NotesBroad knuckle and finger size (~69.5 mm circ). Secure sensor contact without pinching or rotating. |
| RingConn SizeSize 14 | US / Canada14.0 | UK / AustraliaZ+2 | EU / ISO72.0 | Inside Diameter (mm)23.01 mm | Inside Circ. (mm)72.29 mm | Fit & Squircle Sensor NotesLargest produced RingConn size (~72.0 mm circ). Rare extended size among smart rings, accommodating circumferences up to 72.3 mm. |
Smart Ring Sizing: RingConn Gen 2 vs Competitors
Physical dimensions and fit characteristics across leading smart ring manufacturers.
RingConn Gen 2
- Width: 6.8 mm (ultra-slim)
- Thickness: 2.0 mm
- Size Range: US 6 to 14
- Shape: Squircle (anti-spin)
- Fit Nuance: Minimal finger spacing drag; corner clearance required.
Oura Ring Gen 3 / 4
- Width: 7.9 mm
- Thickness: 2.55 mm
- Size Range: US 6 to 13 / 14
- Shape: Round with interior nodes
- Fit Nuance: Dome sensor bumps press slightly into skin.
Samsung Galaxy Ring
- Width: 7.0 mm
- Thickness: 2.6 mm
- Size Range: US 5 to 13
- Shape: Concave round profile
- Fit Nuance: 3 interior sensor nodes require snug contact.
Evie Ring
- Width: 8.0 mm
- Thickness: 3.0 mm
- Size Range: US 5 to 12
- Shape: Open-ring gap design
- Fit Nuance: Open gap flexes ~0.5–1.0 mm for swelling.
The 24-Hour RingConn Sizing Kit Protocol
How to test sample plastic rings and lock in the ideal RingConn Gen 2 size.
- Target finger selection: RingConn strongly recommends your index finger for the highest accuracy in sleep apnea and optical pulse tracking. The middle and ring fingers are also suitable.
- Evaluate knuckle clearance: The squircle sample ring should slide past your knuckle with moderate, gentle friction. If the squared outer corners require soap or painful pressure to cross the knuckle, test the next whole size up.
- Align the dual sensors: Ensure the flat edge containing the two interior sensor nodes rests directly against the fleshy pad on the underside (palmar side) of your finger.
- Wear continuously for 24 hours: Fingers fluctuate by up to 0.7 mm in circumference between morning and evening. Wear the sizing ring through a full night's sleep, handwashing, and exercise before finalizing your size on the RingConn portal.
Source and verification
Table source: RingConn Official — Gen 2 Sizing & Fit Guide. Last reviewed . Check the retailer's current size guide before ordering.
Frequently asked questions
How does the RingConn Gen 2 "squircle" shape affect ring sizing?
The RingConn Gen 2 features an iconic squircle (softly squared outer perimeter with a circular inner cavity). This geometry is specifically engineered to prevent the ring from spinning on your finger, keeping the dual PPG optical sensor nodes firmly anchored against the palmar side where blood perfusion is strongest. Because the interior is circular, it slips over the knuckle like a standard ring, but the corners provide tactile stability that makes it feel slightly more structured than a round metal band.
What sizes are available for the RingConn Gen 2?
The RingConn Gen 2 is manufactured in 9 whole sizes: US 6, 7, 8, 9, 10, 11, 12, 13, and 14. RingConn does not produce half sizes (e.g., 7.5 or 8.5) and does not offer a petite size 5. It is one of the few smart rings to provide an extended size 14, accommodating finger circumferences up to 72.3 mm.
Can I use a RingConn Gen 1 sizing kit to determine my Gen 2 size?
RingConn officially advises using the dedicated Gen 2 sizing kit. While the interior whole-number size diameters remain closely aligned between generations, the Gen 2 has a noticeably thinner 2.0 mm wall profile (compared to 2.6 mm on Gen 1) and reduced 6.8 mm width. Testing with the specific Gen 2 sample ensures you evaluate the exact width and adjacent-finger clearance.
Which finger is best for wearing the RingConn Gen 2?
RingConn recommends wearing the ring on your index finger for the most accurate health and sleep apnea tracking, as the radial digital artery provides optimal optical sensor readings. The middle and ring fingers are also suitable alternatives. The thumb and pinky are not recommended due to looser fit and irregular knuckle geometries.
What should I do if I am between sizes on the RingConn Gen 2?
If your finger falls between whole sizes (for example, if you measure US 7.5 or 8.25), RingConn strongly recommends sizing up to the larger whole size (e.g., choose size 8 for a 7.5 finger). Because fingers naturally swell during sleep, hot weather, and after exercise, a slightly larger size prevents painful restriction while the squircle shape keeps sensors oriented correctly.
What are the dimensions and weight of the RingConn Gen 2?
The RingConn Gen 2 measures 6.8 mm in width and approximately 2.0 mm in thickness, making it noticeably slimmer and more compact than competitors like the Ultrahuman Ring AIR (8.1 mm) or Samsung Galaxy Ring (2.6 mm thick). It weighs approximately 2 to 3 grams depending on size, crafted with an aerospace-grade titanium outer shell and medical-grade epoxy inner lining.
Can the RingConn Gen 2 be resized by a jeweler?
No. Like all smart rings, the RingConn Gen 2 contains an embedded lithium-polymer battery, micro-circuitry, and photoplethysmography sensors hermetically sealed within the band. Applying heat, cutting, or mechanical stretching will permanently destroy the internal hardware and invalidate the warranty.