I was researching foreign credit card transaction fees. In my case, it is for using a USA-issued Visa card that bills in US Dollars $, for transactions in Switzerland using CHF. (I believe the idea here applies to any credit card that bills in a currency other than Swiss Franc and therefore requires currency exchange.)
Also, this is for a credit card that explicitly states it charges no “foreign transaction fees”. You should not be using a credit card for foreign transactions, which charges a “foreign transaction fee”! Speaking of this, exchange rates and currency conversion administrative fees are not included in “foreign transaction fees”.
On to my main point: It is best always to run the credit card transaction in the foreign currency (CHF) rather than in your card’s billing currency ($USD for me). That’s the little message you get from the credit card scanner device, like “Pay in USD $105.23 or CHF 100 ?” You always want to pick CHF here, and never USD $ (or whatever your card’s billing currency is). It may be awfully convenient for the total to show up in your native billing currency (USD), and while it tempts you to select the currency most familiar to you … don’t do that, because selecting the billing currency USD $105.23 here will result in paying 3-15% more fees on the currency exchange involved in that transaction, than if you had chosen the foreign currency CHF.
By selecting the foreign currency CHF (good!), your currency conversion is performed by the card organization (Visa or MasterCard). You want this. If you instead were to select the billing currency (USD for me) – bad! – then the merchant’s point-of-sale system performs the currency exchange. And point-of-sale systems tend to offer a much worse exchange rate to create profit for itself and sometimes for the merchant.
On top of whatever raw exchange rate the transaction runs at, the card organization (Visa/MC) will add in around a 1% currency conversion charge, and the bank that issued your credit card will add in around a 2% administrative fee. And if you are using a card with a “foreign transaction fee”, that will get added in as well but again don’t use a card with a foreign transaction fee!
One last thing, apparently the MasterCard card organization gets slightly better USD → CHF exchange rates than the Visa card organization. For example, using the date of September 26th 2022, Visa exchanges CHF 100 for $102.7220, while MasterCard will exchange CHF 100 for $102.1566.
I found a lot of great information about this here if anybody cares:
Visa vs. MasterCard: Who gives better exchange rates?
Overseas credit card use: Should you pay in SGD or in foreign currency?