When a transaction is made in a country other than that of the card's issuing bank, the card's issuing bank charge a fee to process the transaction. This is know as a "cross-border" fee, as the funds are crossing country borders from the card's issuing bank to our local store bank.
For example, If one uses a Credit Card issued in the United States to buy from China, the cross border fee will apply.
What is the exact fee charged ?
The cross border and currency conversion fee is a small percentage of the overall transaction. Unfortunately there is no way to determine the exact number because the fee is comprised of charges set by the card's issuing bank that are constantly changing.