I see this all over the place and I've by now learned to always answer "no" if anybody offers currency conversion. It's sometimes difficult, because some terminals will only show you a choice of currencies, and you have to remember to pick the local currency (local to the store you are paying in) and let your bank do the conversion at their (terrible) rates, rather than pay a 10% markup.
Same here. I often write down the converted sum and then reject conversion. Later I compare my notes with the the conversion done my bank issue the credit card.
It was always so that my bank was cheaper, until very recently when it would have been to opposite way for the first time. Both my banks have recently raised their conversion fees, I think they are now 2.3% - 2.5%.
That still sounds better than the exorbitant fees some dodgy businesses are charging. I don't know whether it was a rare exception that the bank was more expensive or whether it becomes more common.
