How do you proceed in calculating exchange rates between countries and what data do you need?
Exchange rates are simply market prices of foreign currencies. The price can fluxuate on a daily basis. So, are you asking how you would build a model that predicts an exchange rate? whew lottsa luck on that one. Or are you asking where you can get exchange rates? Newpapers with a financial section carry such information. You could also look on the web site of a major bank. They will often provide foreign currencies for their customers.