When you shop online and want to buy a ring, you need to know the ring size you require. Of course there is an app for it!
This app, if you download to your phone, will help you to correctly measure your size as long as you have a ring that you know you like the size of it.
Unfortunately as far as I know it is only available for Apple devices.
You can download it here

If you do not want to use this app, we can arrange alternative measurement options for you. Just get in touch.