The United States dollar (U.S. dollar or USD) is the national currency of the United States and its territories. USD is considered to be the one of the main reserve currencies (also called an anchor currency) in the world. Besides this, USD has the status of being the official national currency in some other countries or an additional official currency to the national one. All USD that has ever been issued can still be officially used. About 80 percent of the calculated global trading volume is made in USD. Crypto exchanges are no exception and all popular platforms have USD-to-crypto coin currency pairs to trade. In addition, the Bitcoin exchange rate is firstly counted in comparison with USD and then to other popular currencies.