Ring Sizer – Size Your Finger
Measure, Save & Convert Sizes
About
Measure your finger or an existing ring accurately on your iPhone. Get your ring size in multiple international systems, including diameter and circumference. No printing or extra tools needed.
What's New in Ring Sizer
1.0
October 8, 2026
Subscriptions & In-App Purchases
Ring Sizer Weekly
Measure and convert ring sizes for one week
Developer apps
FAQ
How can I find my ring size with Ring Sizer on my iPhone?
You can measure an existing ring directly on your iPhone screen by placing it on the screen and adjusting the on-screen guide to match its inner edge. Alternatively, use the finger measurement flow if you don't have a ring available.
Can I measure a ring I already own with Ring Sizer?
Yes. Place a ring that fits you on the screen and adjust the guide to its inner edge. Ring Sizer will then determine its diameter, circumference, and corresponding ring size.
How can I find my ring size without a ring using Ring Sizer?
Use the finger measurement flow within Ring Sizer. This feature allows you to estimate your ring size without needing an existing ring or a printed ring sizer.
Which ring size systems does Ring Sizer support?
Ring Sizer displays ring sizes in US, UK, EU, and JP systems. It also provides the measured diameter and circumference for further comparison and verification.
Can I use Ring Sizer when buying a ring as a gift?
Yes. If you have access to a ring that fits the intended recipient, you can measure it on your iPhone using Ring Sizer and use the resulting measurements when comparing ring sizes.
Is Ring Sizer useful for jewelers and jewelry sellers?
Yes. Jewelers and sellers can utilize Ring Sizer as a quick tool to measure rings and compare sizes across US, UK, EU, and JP sizing systems, improving customer service.
What are the subscription options for Ring Sizer?
Ring Sizer offers weekly, monthly, and annual subscription plans. There are also yearly plans available at different price points, with some offering free trial periods.
How does the auto-renewal work for Ring Sizer subscriptions?
Your subscription to Ring Sizer will automatically renew unless auto-renewal is turned off at least 24 hours before the end of the current subscription period. The renewal cost depends on your chosen plan.