Here you can find some measurements of the world.
Our size, the first one on the left side ( 16/17/18... ) , represents the internal diameter of the rings. Below, you can make the conversion with the size used in your country. If you have not measured your fingers yet, you can do that in every jewellery.
The real circumference of the ring sometimes could be 0,1/2 millimeter more or less, because all our rings are handmade, so do not take our measurements as absolutely perfect.
If you take the wrong size, you can change it, all informations about changing the size in Support.