There is about $1.2 trillion dollars of U.S. currency in circulation. The Federal Reserve Banks distribute new currency for the U.S. Treasury Department, which prints it. Depository institutions buy currency from Federal Reserve Banks when they need it to meet customer demand, and they deposit cash at the Fed when they have more than they need to meet customer demand. As of July 2013, currency in circulationthat is, U.S. coins and paper currency in the hands of the publictotaled about $1.2 trillion dollars. The amount of cash in circulation has risen rapidly in recent decades and much of the increase has been caused by demand from abroad. The Federal Reserve estimates that the majority of the cash in circulation today is outside the United States. Meeting the Variable Demand for Cash

The public typically obtains its cash from banks by withdrawing cash from automated teller machines (ATMs) or by cashing checks. The amount of cash that the public holds varies seasonally, by the day of the month, and even by the day of the week. For example, people demand a large amount of cash for shopping and vacations during the year-end holiday season. Also, people typically withdraw cash at ATMs over the weekend, so there is more cash in circulation on Monday than on Friday. To meet the demands of their customers, banks get cash from Federal Reserve Banks. Most medium- and large-sized banks maintain reserve accounts at one of the 12 regional Federal Reserve Banks, and they pay for the cash they get from the Fed by having those accounts debited. Some smaller banks maintain their required reserves at larger, "correspondent," banks. The smaller banks get cash through the correspondent banks, which charge a fee for the service. The larger banks get currency from the Fed and pass it on to the smaller banks. When the public's demand for cash declinesafter the holiday season, for examplebanks find they have more cash than they need and they deposit the excess at the Fed. Because banks pay the Fed for cash by having their reserve accounts debited, the level of reserves in the nation's banking system drops when the public's demand for cash rises; similarly, the level rises again when the public's demand for cash subsides and banks ship cash back to the Fed. The Fed offsets variations in the public's demand for cash that could introduce volatility into credit markets by implementing open market operations. The popularization of the ATM in recent years has increased the public's demand for currency and, in turn, the amount of currency that banks order from the Fed. Interestingly, the advent of the ATM has led some banks to request used, fit bills, rather than new bills, because the used bills often work better in the ATMs. Maintaining a Cash Inventory

Each of the 12 Federal Reserve Banks keeps an inventory of cash on hand to meet the needs of the depository institutions in its District. Extended custodial inventory sites in several continents promote the use of U.S. currency internationally, improve the collection of information on currency flows, and help local banks meet the public's demand for U.S. currency. Additions to that supply come directly from the two divisions of the Treasury Department that produce the cash: the Bureau of Engraving and Printing, which prints currency, and the United States Mint, which makes coins. Most of the inventory consists of deposits by banks that had more cash than they needed to serve their customers and deposited the excess at the Fed to help meet their reserve requirements. When a Federal Reserve Bank receives a cash deposit from a bank, it checks the individual notes to determine whether they are fit for future circulation. About one-third of the notes that the Fed receives are not fit, and the Fed destroys them. As shown in the table below, the life of a note varies according to its denomination. For example, a $1 bill, which gets the greatest use, remains in circulation an average of 5.9 years; a $100 bill lasts about 15 years.