1. the complete money (policy) multiplier is calculated as follows: k=(Rc+ 1)/(Rd+Re+Rc). Among them, Rd, Re and Rc respectively represent the statutory reserve ratio, excess reserve ratio and the proportion of cash in deposits. The basic calculation formula of money (policy) multiplier is: money supply/base money. Money supply is equal to the sum of money (that is, cash in circulation) and demand deposits; The base currency is equal to the sum of money and reserves. Money and loans provided by banks will generate several times the income of their deposits through several activities such as deposits and loans, commonly known as derivative deposits. The size of the money multiplier determines the expansion ability of the money supply. 2. The size of currency multiplier is determined by the following four factors: (1) statutory reserve ratio. The statutory reserve ratio for time deposits and demand deposits is directly determined by the central bank. The higher the general statutory reserve ratio, the smaller the currency multiplier; Conversely, the greater the currency multiplier. (2) Excess reserve ratio. The ratio of the reserves held by commercial banks that exceed the statutory reserves to the total deposits is called the excess reserve ratio. Obviously, the existence of excess reserves reduces the ability of banks to create derivative deposits. Therefore, the relationship between the excess reserve ratio and the money multiplier also changes in the opposite direction. The higher the excess reserve ratio, the smaller the currency multiplier. Conversely, the greater the currency multiplier. (3) Cash ratio. The cash ratio refers to the ratio of cash in circulation to demand deposits in commercial banks. The cash ratio is positively related to the demand for money. Therefore, all factors that affect the demand for money will affect the cash ratio. For example, the interest rate of bank deposits is reduced, resulting in a decrease in the income of interest-bearing assets. People will reduce bank deposits and be more willing to hold more cash, thus increasing the cash ratio. The cash ratio is negatively correlated with the currency multiplier. The higher the cash ratio, the more cash exits the expansion process of deposit currency and flows into daily circulation, thus directly reducing the loanable funds of banks, restricting the ability of deposit derivation, and the smaller the currency multiplier. (4) The ratio of time deposits to demand deposits. Because the derivative ability of time deposits is lower than that of demand deposits, central banks have set different statutory reserve ratios for different types of commercial bank deposits. Usually, the statutory reserve ratio of time deposits is lower than that of demand deposits. In this way, even if the statutory reserve ratio remains unchanged, the change of the ratio of time deposits to demand deposits will also cause the change of the actual average statutory reserve ratio, and ultimately affect the size of the currency multiplier. Generally speaking, when other factors remain unchanged, when the ratio of time deposits to demand deposits rises, the currency multiplier will become larger; On the contrary, the currency multiplier will become smaller. In short, the size of the currency multiplier is mainly determined by the statutory reserve ratio, excess reserve ratio, cash ratio and the ratio of time deposits to demand deposits. In addition to the above four factors, there are two special factors that affect China's currency multiplier: fiscal deposits and credit plan management.