You have to take your measurements and check out your size in the size chart here. Under the charts, you will find tips on how to take them and on how to pick a size.
I don’t recommend to choose a size based on something from elsewhere as each brand has its own size chart which of course are different from one brand to another.
On a side note, I don’t advice to pick your size after checking the equivalent from one country to another as size charts vary from one brand to another, sometimes inside a country itself as well. Small differences could lead you picking the wrong size, checking your size with your measurements shouldn't :)