All rings are listed in Australian/UK format (A,B,C etc.) Most ready to ship rings can only be upsized by 0.5 to 1 size, so if you would like something made in your size you can email to arrange a custom ring order.
If you don’t know your ring size you can purchase a ring sizer here, or head into your local jewellery store and they will measure you.
Make sure you get the size of the particular finger you want to wear it on, as all your fingers are different! Even the same finger on the opposing hand can be half a size or so different.
Resizing is available at a cost.