There are no rules obliging traders to trade for currencies in any specific way. It’s up to them. Anyone can become a trader, just by creating an account with forex broker, and there are millions. But it is the really big banks and brokerages, with the most money online, that have the greatest influence on how exchange rates are determined, and these houses proceed according to some basic guidelines.
The currency calculator permits you to determine how much you will receive in foreign currency in exchange for you own. Input the exchange rate and the amount you wish to exchange. If you do not know the rate, use the link to look up the exchange rate.