How Central Banks Control the Money Supply with Interest Rates

Many people think that the central bank primarily controls the money supply (M1, M2, M3). That used to be true. However, since the bulk of money creation is done by private banks, the central bank mainly controls their money creation by setting the short term interest rate (rbi policy rate, rbi repo rate, ecb deposit rate, fed funds rate, Bank of England base rate) on bank loans and on central bank reserves.
n most cases, monetary policy boils down to the following. Central bank set the interest rate on which all other rates are based. By doing so they try to control the amount of money circulating in the economy indirectly by making it more or less attractive for commercial banks to lend. Most central bankers change the interest rate as they try to control inflation. They will increase the interest if they believe the economy is overheating. This will lower inflation. They decrease the interest rate to spur the economy to grow faster which will lead to increased inflation.

Monetary policy via interest rates is part of the monetary policy toolkit of central banks. In addition to that central banks can engage in money printing, monetary finance, and quantitative easing. I have separate videos on each of these topics.