What is the United States Dollar (USD)? The United States Dollar refers to the national currency of the U.S and is represented by the ISO code USD and is often abbreviated as US$. It is considered a standard currency and is the most widely used currency in international transactions. The USD, or United States Dollar, is the official currency of the U.S. and the world's primary reserve currency , crucial for global trade, finance, and economic stability. Learn about its history, usage, value & importance in the global economy. All Circulating Denominations Each note includes security and design features unique to how the denomination is used in circulation. The U.S. government periodically redesigns Federal Reserve notes to make them easier to use, but more difficult to counterfeit. It is U.S. government policy that all designs of U.S currency remain legal tender, regardless of when they were issued. This policy includes all denominations of Federal Reserve notes, from 1914 to the present. Calculate live currency and foreign exchange rates with the free Xe Currency Converter . Convert between all major global currencies, precious metals, and crypto with this currency calculator and view the live mid-market rates.
