FitMyRing vs DIAMETRO

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.

Find your ring size in seconds, right on your iPhone. Place a ring you already own on the calibrated circle, slide until the bubble fills the inside of the ring, and DIAMETRO shows its size in EU/ISO, US, UK, CH and JP, plus the exact diameter and circumference. HOW IT WORKS • Calibrate once with a bank card or a coin for true physical scale • Lay your ring on the screen • Slide until it fits, then save the result DIAMETRO PRO • Finger measurement: enter the circumference of your finger and get a recommended size, with optional knuckle compensation • All accent colors • Unlimited saved measurements • Printable PDF sizer, export and backup (PDF, CSV, JSON) ALSO INSIDE • Light and Dark mode • English, Romanian and French PRIVATE BY DESIGN No account. No tracking. Your measurements stay on your device. Conversions are approximate. Confirm your size with a jeweler before buying.