Smart Health Ring – Size Chart

Sizes refer to the inner diameter of the ring in millimeters. Use the guide below to find your perfect fit.

How to Measure Your Finger

  1. Wrap a thin strip of paper snugly around the finger you plan to wear the ring on
  2. Mark where the paper overlaps, then measure that length in mm
  3. Divide by 3.14 to get your inner diameter
  4. Match the result to the chart below
Size Inner Diameter Inner Circumference US Size Best For
17 17 mm 53 mm 6 – 7 Small / slender fingers
20 20 mm 63 mm 10 Average adult fingers
22 22 mm 69 mm 12 – 13 Large / wide fingers

Between sizes? Size up for a comfortable all-day fit. Wear the ring on the index or middle finger of your non-dominant hand for best sensor accuracy.