Smart rings (Oura, RingConn) and silicone bands (Qalo, Ridge) do not follow standard jewelry sizing. Here is how to measure them correctly.
Smart rings house rigid batteries and sensors that cannot flex over your knuckle. Furthermore, they require constant, snug skin contact on the underside of the finger to capture heart rate and temperature data accurately.
Do NOT use standard US ring sizes for Oura or RingConn. Both companies explicitly state their sizes deviate from standard jeweler sizes. You must order their physical sizing kits, wear the plastic sizer for 24 hours, and then submit your size.
Silicone rings flex heavily. Most brands recommend sizing down if you are a half size, because silicone grips the skin tightly and naturally stretches slightly over time through wear and tear.
Evelyn is a certified GIA Gemologist with over a decade of experience in fine jewelry sizing and design. She ensures all conversion charts and measuring advice strictly adhere to ISO 8653 standards.