Economic understanding of the real sector, fiscal sector, external sector and monetary sectors are the key to monetary policy and national budget. In brief, through the overall balance of the external sector, the net foreign assets of the monetary sector are linked. The government's national domestic budget deficit is financed from banking sources. Real sector GDP and inflation are related to the fiscal sector and money supply estimation, for example. The government and Bangladesh Bank's (BB) meticulous policy formulation regarding discussed output, inflation, interest rate, and exchange rate consistently impact the four sectors with robust outcomes in the economy, taking care of aggregate demand and supply. Changes in money supply and fiscal policy, for instance, increase or decrease the aggregate demand. While aggregate supply depends on the production of commodities, minerals, energy, and others, it relies on domestic and global price development. As a market maker, to ensure a monetary transmission mechanism, BB needs to play a proactive role in incorporating the right number for fixing lending rates and other rates, for instance, addressing the structural rigidity of the economy. As we are in the process of graduating as a developing country facing an open economy, we need to use real interest rates and real exchange rates, the tools of monetary policy derived from the monetary conditions index, for near (nowcasting) and medium-term forecasting of GDP and inflation in relation to the autoregressive and structural model. Effective money supply and budgetary expenses, along with external and real sectors, taking care of marginal groups of people in the society can ensure the welfare of the economy.