Originally Posted by Adraco

No, but an ATM does not in itself have a currency exchange rate. It will debit the card the amount withdrawn, and the card company, Visa or MasterCard will then do all the exchanges and conversions and add their fees. That is never done at the ATM itself.

The ATM will only record the transaction, $100 USD withdrawn. Then the rest takes place in backoffice functions. You said ~"what ever exchange the ATM is using" and the ATM does not use any exchange rate, since it will only debit in it's own "home" currency, the one currency it's giving out. Then the ATM's mother bank will settle the debt with the card company, which then in turn will settle with the customer.