Most banks just let visa/mastercard do the exchange and maybe tac on a % fee. So the bank doesn't list an exchange rate because they don't maintain one. So find out in advance if your bank adds a fee and then check Visa [1] or mastercard [2] when you actually need to work it out.
[1] https://usa.visa.com/support/consumer/travel-support/exchang...
[2] https://www.mastercard.us/en-us/personal/get-support/convert...