About Ring Sizer
Ring Sizer and this website are created by Marwan Akhandaf, the independent developer behind the Ring Sizer iPhone and iPad app. This page explains who is responsible for the content, where the sizing numbers come from, and what the tools can and cannot promise.
Who creates Ring Sizer and these guides?
Marwan designs and develops the app, maintains the conversion data used by both the app and this site, and writes the measurement guides published here. The aim is practical: give someone buying a ring online a measurement they can understand, convert and verify before spending money.
The site is independent. It is not a jewellery shop, it does not sell rings, and it receives no commission for recommending one sizing method over another. App Store links lead only to the Ring Sizer app. This separation matters because the most accurate advice is sometimes to stop measuring at home and ask a jeweller, especially for an expensive ring or one that cannot be resized.
How are ring sizes calculated and checked?
Every system describes the same physical object: the inside of a ring. The conversion table begins with inner diameter and circumference in millimetres, then maps those measurements to the labels used in the United States, United Kingdom, Europe, Japan, China and Russia. The same table powers the browser converter and the app, so a value does not change when you move between them.
The methodology follows the measurement and designation principles in ISO 8653:2016, the current international standard for ring sizes. Screen measurements depend on physical scale, so Ring Sizer identifies the iPhone model and uses that display’s known pixel density before drawing a gauge. A manual check can use an ID-1 bank card, whose dimensions are defined by ISO/IEC 7810, rather than an object with an uncertain size.
What sources support the practical measurements?
Where a guide recommends a reference object, it links to the authority that publishes that object’s dimensions. The United States Mint lists a US quarter at 24.26 mm across, and the Royal Mint lists the current twelve-sided £1 coin at 23.43 mm point to point. Those sources are more reliable than copying a number from another sizing blog.
Articles distinguish measured facts from practical fit guidance. Temperature, knuckle shape, band width and interior profile can all change which nominal size feels comfortable, so those pages explain the uncertainty instead of presenting a universal rule. Publication and modification dates reflect when a page was actually released or materially revised.
What can the site not guarantee?
No app, printout or article can guarantee that a finished ring will fit. Fingers change during the day, manufacturers round differently, and two bands carrying the same size label can feel different. The tools here are intended to reduce avoidable errors and give you a millimetre measurement a seller can interpret. They are not a substitute for a professional fitting when a mistake would be costly.
Virtual try-on is also separate from measurement. It can help you judge style and proportion from a photo, but a photo of a hand without a known-size reference has no dependable physical scale. The guides say so wherever the distinction matters.
How can you report a correction?
If a conversion, source link or explanation appears wrong, email hello@ringsizerr.com with the page address and the value in question. Corrections are checked against the underlying measurement table and the cited primary source before the page is updated. Commercial placement requests do not influence the conversion data or editorial recommendations.