Explain the difference between the total supply of money at the central bank and the total supply money in the economy at equilibrium

When the monetary market is at equilibrium, the supply and demand for money match. The primary reason why the money supply at the central bank is different than the total supply of money is because the central bank only manages a certain portion of the money supply. The central bank reports the total physical currency (cash) and all the reserves it holds for commercial banks. This is only a portion of the total money supply.

The total money supply includes what is reported by the central bank and, just to name a few, those checking, savings, money market accounts and cash deposits (CD's) account balances. Even though these accounts are non-physical currency, they do represent a digital monetary value that can be converted into cash. This is why the total money supply is higher than the money supply at the central bank.