The budget is an act that estimates revenues, receipts and expenditures, expenses for a certain period, usually one year. It consists of a general part, a special part and a plan of development programs. There are three levels of the general government budget, namely the state budget, the budget outside the budget users and public enterprises, and the budget of local units. In this final paper, the budget of local units is analyzed on the example of the City of Belišće. Belišće is a small town in Osijek-Baranja County that has been known for its paper industry since its beginnings, thanks to the company Kombinat. However, after the collapse of Kombinat, a large number of people remained unemployed and there was a general decline in the economy. Today, Belišće is slowly recovering, and through the budget a progress over a five-year period was analyzed. Given that Belišće and Valpovo are neighboring cities of similar development progress, they are compared with the general characteristics of cities and budgets. Budget data were compared in relation to the number of inhabitants, and then the simulations of the joint budget were continued on this data, with special emphasis on the simulation of the joint administration. Based on the simulation, a conclusion was drawn.