Ring sizing can be a bit of a tricky question and is a highly personal choice. Some people like their rings loose, some like them tight. If you're unsure and live in Stockholm you are more than welcome to get in touch and come by and try out your size. Otherwise, you can always go and see a local jeweller and get your finger measured.
The type of measurement I use is the inner diameter of the ring, for example 17, which means the inner diameter is 17mm.
If you have ordered a ring from me before, let me know and I'll find your size!