Karat: Ring Sizer & Measure

Find your ring size in under a minute — no printables, no guessing, no trip to the jeweler.
Karat turns your iPhone into a precise ring sizer. Place any ring on the screen, match the golden circle to its inside edge, and instantly get your size in US, UK, EU, TR and JP standards — plus the exact diameter in millimeters.
PLANNING A SURPRISE PROPOSAL?
Borrow one of their rings for 60 seconds. Measure it quietly, save it as "Her size" or "His size", and hand the jeweler an exact number. The secret stays safe — and the ring fits on the first try.
HOW IT WORKS
1. Calibrate once — Karat auto-detects your iPhone model for millimeter accuracy (you can verify with any bank card).
2. Place a ring on the screen and match the circle — or measure your finger directly between the guides.
3. Get your size instantly, in every international standard.
WHY KARAT
• Ring measurement using your existing ring — the most accurate phone-based method
• Finger measurement mode when you don't have a ring at hand
• Full conversion chart: US · UK · EU · TR · JP · mm
• Save unlimited sizes: yours, your partner's, gifts for family
• Sizing tips from jewelers: when fingers swell, how wide bands fit, comfort fit vs standard
• Works 100% offline. No account. No location. Your data never leaves your phone.
ACCURACY YOU CAN TRUST
Karat calibrates to your exact screen down to the pixel-per-millimeter. For important purchases like engagement rings, we still recommend confirming with a professional jeweler — Karat gets you the right starting size without leaving home.
Your first measurement is free. Unlock unlimited measurements, saved sizes and the full conversion chart with Karat Pro.
KARAT PRO SUBSCRIPTION
Karat Pro is available as an auto-renewing weekly subscription. The price is shown in the app before purchase. Payment will be charged to your Apple ID account at confirmation of purchase. The subscription automatically renews unless it is canceled at least 24 hours before the end of the current period. Your account will be charged for renewal within 24 hours prior to the end of the current period. You can manage and cancel your subscriptions anytime in your App Store account settings after purchase.
Privacy Policy: https://usappstudio.com/privacy-policy
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/