FitMyRing

Measure a ring's inner size directly on your iPhone or iPad screen. Place the ring on the display, move the circle into the ring opening, and pinch with two fingers until the circle matches the inner edge. The app shows the diameter, radius, circumference, and nearest sizes for Metric, US/CA, UK/AU, EU/ISO, and JP/CN systems. FitMyRing works locally on your device. It does not use a camera, account, server, cloud sync, ads, or analytics. Measurements are for reference. For expensive purchases or resizing, confirm the size with a jeweler.