Hi Hubertus 👋
The time it takes for a payment to be final can vary based on when we receive the clearing message from Mastercard. It's at this point we finalise the payment with the realtime Mastercard exchange rate, and that's the amount that you are charged.
Looking into our previous foreign currency transactions, we see that the vast majority of transactions are finalised within 2 days, 98% of transactions to be precise (with 75% of transactions being finalised in just over half a day).
in terms of how you can see that you're payment is final, it will no longer show up in your events overview as pending, with the message describing that the payment may change slightly based on the exchange rate. You can see an example of a finalised foreign currency payment in this post by Simon M (thanks @Simon M 😊)
I hope this answers you're question, please feel free to respond if you would like more information 🌈