RingSizer – Ring Size Tool

Measure & Convert Ring Sizes

Only for iPhone

Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.

iPhone

Measure your ring size in seconds — no physical ring sizer needed. Precision jeweler-grade accuracy, right from your iPhone screen. RingSizer turns your iPhone into a precision jeweler's tool — no ring sizer, no guesswork, no trip to the store. MEASURE YOUR RING Already have a ring that fits? Place it flat on your screen and align it with the on-screen guide. RingSizer uses your device's exact screen dimensions — with optional bank-card calibration for extra precision — to calculate your true size. MEASURE YOUR FINGER No ring on hand? Use the two-step Ellipse Method. Fingers aren't perfectly round, so RingSizer measures both width and thickness for a scientifically accurate fit, based on the same math jewelers use. CONVERT BETWEEN SYSTEMS Instantly convert between EU, US, UK, Japanese, Australian and Swiss/German ring sizes — or look up any size by diameter and circumference. LIFE-SIZE RULER A true-to-scale on-screen ruler for measuring anything small, in mm, cm or inches. FEATURES • High-accuracy ellipse-based finger measurement • Bank-card screen calibration for pixel-perfect results • Worldwide size conversion (EU, US, UK, JP, AU, CH/DE) • Save and organize your measurement history • Evening measurement reminder — fingers swell throughout the day, so a second reading helps you land on your truest size • Private by design — your measurements never leave your device RingSizer Premium unlocks unlimited history, expert fitting advice, and full worldwide size conversion — with a one-time purchase, no subscription. Whether you're buying a ring as a surprise, replacing a lost one, or shopping online, RingSizer gives you a confident, accurate answer in seconds.

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The developer, ReflectBuddy, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Used to Track You

    The following data may be used to track you across apps and websites owned by other companies:

    • Location
    • Identifiers
    • Usage Data
    • Diagnostics

  • Data Linked to You

    The following data may be collected and linked to your identity:

    • Location
    • Identifiers
    • Usage Data
    • Diagnostics

  • Data Not Linked to You

    The following data may be collected but it is not linked to your identity:

    • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Seller
REVIEWELL
Size
1.5 MB
Category
Utilities
Compatibility
Requires iOS 17.0 or later.
  • iPhone
    Requires iOS 17.0 or later.
  • Mac
    Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
  • Apple Vision
    Requires visionOS 1.0 or later.
Languages
English
Age Rating
4+
In-App Purchases
Yes
Copyright
REVIEWELL BV © 2026
  • Developer Website
  • Privacy Policy

    • More by ReflectBuddy

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