10 minutes. According to the website of the Federal Reserve Bank, the exchange rate changes at any time and can only be updated once every 10 minute to keep up with the pace of exchange rate changes, so the exchange rate of the US dollar is updated once every 10 minute. Exchange rate, also known as foreign exchange rate, foreign exchange rate or foreign exchange market, refers to the exchange rate between two currencies, and can also be regarded as the value of one country's currency against another's currency.