An iOS app that turns your iPhone screen into an accurate ring sizer — no extra tools needed.
- Measure a ring — Place an existing ring over the on-screen circle and pinch-to-zoom until the edges align
- Measure your finger — Match a bar to your finger's width for a direct size recommendation
- Multiple size standards — Results shown in US, EU, UK, JP, HK, and CN sizing simultaneously
Before measuring, you calibrate the app once by placing a standard credit card (85.6 × 53.98 mm) over a blue rectangle and dragging a slider until the edges match. This establishes an accurate points-per-millimetre scale for your specific device, which is then used for all measurements.
- iOS 17+
- Xcode 16+
- Swift 5.9+
git clone git@github.com:mi-apps/ring-sizer.gitOpen Ring Sizer/Ring Sizer.xcodeproj in Xcode, select your target device, and press Run.
Ring Sizer stores only your calibration data locally on your device using SwiftData. No personal data is collected, transmitted, or shared.
Questions or suggestions? Reach out at mi.apps.requests@gmail.com or open an issue.
MIT License — see LICENSE for details.