Free Ring Sizer App for iPhone
No paper. No guesswork. Place your ring on your iPhone screen and get your exact ring size in seconds — free ring sizer app with instant results.
4.8★
App Store Rating
5.84k+
Downloads
6k+
Sizes Found
Online Tool
Step 1: Calibrate Your Screen
Place a standard credit card on your screen. We'll use it to calibrate pixel density for accuracy.
Place your ring on the screen and drag the handles to match its inner edge.
Your Ring Size
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US Size
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UK Size
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EU Size
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Japan Size
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Diameter (mm)
Note: For maximum accuracy, calibrate your screen using a credit card first. Want even more precision? Download our app for advanced features, size history, and family profiles.
Calibration
A standard credit card is 85.6mm wide. Drag the handles below to match your card's width exactly.
Features
Accurate Measurement
Measure your ring size precisely without any external tools.
Save Family Profiles
Quick measurements with the option to save sizes for everyone.
Global Size Standards
Supports US, UK, EU, Japan, and more regional size standards.
Finger Measurement Too
Don't have a ring? Measure your finger directly on screen.
Offline & Private
Works fully offline. Your data never leaves your device.
Instant Results
Your size appears immediately in all major standards — US, UK, EU, and more.
Simple Process
Place Your Ring
Lay your ring flat on the iPhone screen — no paper or tools needed.
Align the Edges
Drag the on-screen guide to match the inner edge of your ring.
Get Your Size
Your exact ring size in every standard is shown instantly.
FAQ
Our app uses precise calibration to match your ring to on-screen guides, ensuring highly accurate results comparable to professional jeweler tools.
No external tools or printouts are required. Simply use your iPhone screen to measure your ring or finger.
Ring Sizer supports multiple regional size systems including US/Canada, UK, Europe, Japan, and more.
Yes. All measurements are stored locally on your device and the app works completely offline. We never collect, share, or sell your data.
Yes! You can measure your ring size for free. The Pro version unlocks unlimited measurements, saves multiple profiles, and offers advanced features.
Free to download. Works on any iPhone. No tools needed.
iPhone only · iOS 17 or later